Define complete Rust API mapping schema

.gitignore

@@ -1,3 +1,4 @@
 /target/
+__pycache__/
 /tools/api-catalog/bin/
 /tools/api-catalog/obj/

README.md

@@ -15,13 +15,15 @@ The source snapshot, compatibility rules, dependency research, and ordered
 implementation plan are in [RUSTREWRITE.md](RUSTREWRITE.md).
 
 The authoritative compiled .NET surface is checked in as
-[`api/public-api.json`](api/public-api.json); [`api/README.md`](api/README.md)
-documents deterministic regeneration and the external types that must be
-mapped to native Rust equivalents.
+[`api/public-api.json`](api/public-api.json). Every type and member has a
+reviewed Rust destination in [`api/RUST-TYPES.tsv`](api/RUST-TYPES.tsv) and
+[`api/RUST-MAPPING.tsv`](api/RUST-MAPPING.tsv); [`api/README.md`](api/README.md)
+documents deterministic regeneration and validation.
 
 ```sh
 cargo build --workspace
 cargo test --workspace --no-run
+python3 tools/generate_rust_mapping.py --check
 ```
 
 Running `cargo test --workspace` is intentionally red during the shim stage.

RUSTREWRITE.md

@@ -22,8 +22,11 @@ Generated inventories are intentionally checked in:
   projects, including a SHA-256 digest.
 - `api/public-api.json` is the authoritative compiled-metadata catalog for all
   13 library assemblies after all six source generators run. It also records
-  every external type referenced by a public signature as a pending Rust
-  mapping obligation.
+  every external type referenced by a public signature.
+- `api/RUST-TYPES.tsv` resolves all 3,066 public and 142 external signature
+  types, plus two support traits referenced by public inheritance metadata.
+- `api/RUST-MAPPING.tsv` records the reviewed Rust destination and complete
+  signature decision for all 30,789 public members.
 - `tests/upstream-tests.json` records every NUnit invocation and the SHA-256 of
   its C# method body.
 - `tests/PARITY.md` maps every NUnit invocation to its Rust test name.
@@ -45,8 +48,8 @@ The current workspace is a structural baseline, not a working client:
 - 1,705 public C# type declarations produce compiling Rust type/trait shims;
 - 12,195 public declaration lines are retained in the API ledger;
 - compiled metadata records 3,066 public types and 30,789 public members with
-  matching independent ECMA-335 counts, plus 142 external signature types that
-  still require explicit Rust mapping decisions;
+  matching independent ECMA-335 counts, with all 142 external signature types
+  resolved to cross-platform Rust or project-owned boundary types;
 - all 1,295 NUnit `[Test]`/`[TestCase]` invocations have compiling Rust test
   entries that intentionally panic with their source identity and body hash;
 - all nine sample/tool projects have compiling Rust binary targets;
@@ -166,6 +169,33 @@ Apply these rules consistently:
 | vectors/quaternions/matrices | compatibility structs with LibreMetaverse field/order semantics; use `glam` internally after parity tests prove conversions |
 | dependency injection container | normal constructors and explicit trait parameters; add no service-locator equivalent |
 
+The checked-in mapping ledgers make those rules concrete:
+
+- properties become getter/setter methods; indexers become `item`/`set_item`
+  methods with their index parameters;
+- events become typed subscriptions returning a guard; stored delegates become
+  `Fn` callbacks, while CLR `BeginInvoke`/`EndInvoke` rows are retained as
+  intentional differences;
+- `in` borrows immutably, `ref` borrows mutably, and `out` is a mutable output;
+  optional parameters use `Option<T>` rather than Rust default arguments;
+- nullable values use `Option<T>` at the exact metadata node, including nested
+  generic arguments;
+- inheritance maps to traits and composition rather than class inheritance;
+  generic parameters retain their names and cataloged constraints as explicit
+  Rust bounds recorded in the mapping ledgers;
+- operators receive stable trait-style names; overloads receive parameter-based
+  descriptive suffixes and a stable ID suffix only when necessary;
+- `[Flags]` enums use `bitflags` with unknown bits retained; wire enums use their
+  exact width/discriminants and an `Unknown(raw)` form only when extensible;
+- all third-party types exposed by C# signatures map through project-owned
+  cross-platform boundary types. No mapping may name a macOS-only API unless
+  equivalent Linux and Windows implementations are provided.
+
+Run `python3 tools/generate_rust_mapping.py --check` after any catalog or mapping
+rule change. It regenerates in memory and rejects duplicate source IDs or Rust
+destinations, stale/missing members, unresolved referenced types, invalid
+statuses, missing assembly representatives, and platform-specific targets.
+
 Public structs and enums that come from the protocol must be `#[non_exhaustive]`
 when servers may add values. Do not derive `Serialize`/`Deserialize` as a
 substitute for the specified wire encoding: LLUDP, LLSD, MessagePack, asset

api/MAPPING-COVERAGE.md

@@ -0,0 +1,53 @@
+# Rust mapping coverage
+
+Generated by `python3 tools/generate_rust_mapping.py`; do not edit by hand.
+
+## Gate
+
+- C# public types mapped: **3,066 / 3,066 (100%)**
+- C# public members mapped: **30,789 / 30,789 (100%)**
+- External signature types resolved: **142 / 142 (100%)**
+- Duplicate C# IDs: **0**
+- Duplicate Rust destinations: **0**
+- Stale or missing catalog IDs: **0**
+- Unresolved referenced types: **0**
+- Platform-specific mappings: **0**
+
+## Assembly representatives
+
+| Assembly | Rust crate | Members | Representative mapping |
+|---|---|---:|---|
+| `LibreMetaverse` | `libremetaverse` | 27,281 | `E:LibreMetaverse.AgentManager.AgentDataReply` -> `libremetaverse::AgentManager::agent_data_reply` |
+| `LibreMetaverse.Imaging.Abstractions` | `libremetaverse-imaging` | 20 | `F:LibreMetaverse.Imaging.ManagedImage.Alpha` -> `libremetaverse_imaging::ManagedImage::alpha` |
+| `LibreMetaverse.Imaging.Skia` | `libremetaverse-imaging-skia` | 3 | `M:LibreMetaverse.Imaging.Skia.SkiaTextureCodec.#ctor` -> `libremetaverse_imaging_skia::SkiaTextureCodec::new` |
+| `LibreMetaverse.LslTools` | `libremetaverse-lsl-tools` | 768 | `F:LibreMetaverse.LslTools.CSToolsException.handled` -> `libremetaverse_lsl_tools::CSToolsException::handled` |
+| `LibreMetaverse.PrimMesher` | `libremetaverse-prim-mesher` | 207 | `F:LibreMetaverse.PrimMesher.Coord.X` -> `libremetaverse_prim_mesher::Coord::x` |
+| `LibreMetaverse.RLV` | `libremetaverse-rlv` | 499 | `E:LibreMetaverse.RLV.RlvRestrictionManager.RestrictionUpdated` -> `libremetaverse_rlv::RlvRestrictionManager::restriction_updated` |
+| `LibreMetaverse.Rendering.MeshFoundry` | `libremetaverse-rendering-mesh-foundry` | 14 | `M:LibreMetaverse.Rendering.MeshFoundry.#ctor` -> `libremetaverse_rendering_mesh_foundry::MeshFoundry::new` |
+| `LibreMetaverse.Rendering.Simple` | `libremetaverse-rendering-simple` | 6 | `M:LibreMetaverse.Rendering.SimpleRenderer.#ctor` -> `libremetaverse_rendering_simple::SimpleRenderer::new` |
+| `LibreMetaverse.StructuredData` | `libremetaverse-structured-data` | 295 | `F:LibreMetaverse.StructuredData.OSDFormat.Binary` -> `libremetaverse_structured_data::OSDFormat::Binary` |
+| `LibreMetaverse.Types` | `libremetaverse-types` | 942 | `F:LibreMetaverse.AssetType.Animation` -> `libremetaverse_types::AssetType::Animation` |
+| `LibreMetaverse.Utilities` | `libremetaverse-utilities` | 13 | `F:LibreMetaverse.Utilities.WaterType.Dry` -> `libremetaverse_utilities::WaterType::Dry` |
+| `LibreMetaverse.Voice.Vivox` | `libremetaverse-voice-vivox` | 531 | `E:LibreMetaverse.Voice.Vivox.TCPPipe.OnDisconnected` -> `libremetaverse_voice_vivox::TCPPipe::on_disconnected` |
+| `LibreMetaverse.Voice.WebRTC` | `libremetaverse-voice-webrtc` | 210 | `E:LibreMetaverse.AudioDevice.OnAudioSourceEncodedSample` -> `libremetaverse_voice_webrtc::libre_metaverse::AudioDevice::on_audio_source_encoded_sample` |
+
+## External replacement decisions
+
+External member APIs are not copied. Each signature type resolves to Rust core/std, an adopted cross-platform crate, or a project-owned native compatibility type.
+
+| Decision | Types |
+|---|---:|
+| `language` | 25 |
+| `native_cross_platform_replacement` | 64 |
+| `stdlib_or_adopted_crate` | 53 |
+
+## Schema decisions exercised
+
+- Properties/indexers/events: **5,090 / 11 / 268**
+- Delegates and flags enums: **40 / 46**
+- Optional/ref/out/in parameters: **470 / 6,144 / 555 / 0**
+- Async Rust signatures: **360**
+- Descriptively renamed overloads: **7,131**
+- Explicit CLR delegate APM differences: **80**
+
+Run `python3 tools/generate_rust_mapping.py --check` to regenerate in memory and enforce the complete gate.

api/README.md

@@ -12,10 +12,13 @@ LibreMetaverse library assemblies at the pinned upstream commit. It contains:
   every LibreMetaverse API that uses them.
 
 External entries are replacement obligations, not copied dependency APIs.
-Issue #3 must map each one to a Rust crate/path: use Rust core/std or an adopted
-crate where it preserves the contract, otherwise define a native MetaCrate
-type. The catalog deliberately does not enumerate members of SkiaSharp,
-SIPSorcery, MessagePack, CoreJ2K, or any other external assembly.
+`RUST-TYPES.tsv` resolves every entry to Rust core/std, an adopted
+cross-platform crate, or a native MetaCrate type. Third-party API objects use
+project-owned boundary types so their eventual backend can be replaced without
+exposing SkiaSharp, SIPSorcery, MessagePack, CoreJ2K, or another foreign member
+surface. `RUST-MAPPING.tsv` records one reviewed destination and full Rust
+signature for every catalog member. `MAPPING-COVERAGE.md` is the readable gate
+summary.
 
 Regenerate from the clean pinned upstream checkout:
 
@@ -28,3 +31,17 @@ extractor twice against the same compiled metadata, rejects count mismatches or
 duplicate documentation IDs, and writes the result only when both outputs are
 byte-identical. The extractor is development-only and is absent from every
 Cargo manifest and published Rust dependency graph.
+
+Regenerate or validate the Rust mapping with only Python's standard library:
+
+```sh
+python3 tools/generate_rust_mapping.py
+python3 tools/generate_rust_mapping.py --check
+```
+
+The checker rejects duplicate C# IDs, duplicate Rust destinations, invalid
+statuses, stale or missing catalog entries, unresolved signature types,
+assemblies without representative mappings, and platform-specific API targets.
+The two support traits in `RUST-TYPES.tsv` are included because compiled public
+inheritance records reference them even though they are absent from the public
+type table.

tools/generate_rust_mapping.py

@@ -0,0 +1,783 @@
+#!/usr/bin/env python3
+"""Generate and validate the reviewed C# to Rust public API mapping ledgers."""
+
+from __future__ import annotations
+
+import argparse
+import csv
+import hashlib
+import io
+import json
+import keyword
+import re
+from collections import Counter, defaultdict
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+CATALOG = ROOT / "api/public-api.json"
+MEMBER_LEDGER = ROOT / "api/RUST-MAPPING.tsv"
+TYPE_LEDGER = ROOT / "api/RUST-TYPES.tsv"
+COVERAGE = ROOT / "api/MAPPING-COVERAGE.md"
+
+ASSEMBLY_CRATES = {
+    "LibreMetaverse": "libremetaverse",
+    "LibreMetaverse.Imaging.Abstractions": "libremetaverse-imaging",
+    "LibreMetaverse.Imaging.Skia": "libremetaverse-imaging-skia",
+    "LibreMetaverse.LslTools": "libremetaverse-lsl-tools",
+    "LibreMetaverse.PrimMesher": "libremetaverse-prim-mesher",
+    "LibreMetaverse.RLV": "libremetaverse-rlv",
+    "LibreMetaverse.Rendering.MeshFoundry": "libremetaverse-rendering-mesh-foundry",
+    "LibreMetaverse.Rendering.Simple": "libremetaverse-rendering-simple",
+    "LibreMetaverse.StructuredData": "libremetaverse-structured-data",
+    "LibreMetaverse.Types": "libremetaverse-types",
+    "LibreMetaverse.Utilities": "libremetaverse-utilities",
+    "LibreMetaverse.Voice.Vivox": "libremetaverse-voice-vivox",
+    "LibreMetaverse.Voice.WebRTC": "libremetaverse-voice-webrtc",
+}
+
+PRIMITIVES = {
+    "System.Boolean": "bool",
+    "System.Byte": "u8",
+    "System.SByte": "i8",
+    "System.Int16": "i16",
+    "System.UInt16": "u16",
+    "System.Int32": "i32",
+    "System.UInt32": "u32",
+    "System.Int64": "i64",
+    "System.UInt64": "u64",
+    "System.IntPtr": "isize",
+    "System.UIntPtr": "usize",
+    "System.Single": "f32",
+    "System.Double": "f64",
+    "System.Void": "()",
+    "System.String": "String",
+}
+
+STDLIB = {
+    "System.Array": "Vec<T>",
+    "System.ArraySegment": "libremetaverse_types::compat::ArraySegment<T>",
+    "System.Collections.BitArray": "Vec<bool>",
+    "System.Collections.Generic.Dictionary": "std::collections::HashMap<K, V>",
+    "System.Collections.Generic.Dictionary.KeyCollection": "libremetaverse_types::compat::DictionaryKeys<K, V>",
+    "System.Collections.Generic.HashSet": "std::collections::HashSet<T>",
+    "System.Collections.Generic.ICollection": "Vec<T>",
+    "System.Collections.Generic.IEnumerable": "Box<dyn Iterator<Item = T>>",
+    "System.Collections.Generic.IEnumerator": "Box<dyn Iterator<Item = T>>",
+    "System.Collections.Generic.IList": "Vec<T>",
+    "System.Collections.Generic.IReadOnlyCollection": "Vec<T>",
+    "System.Collections.Generic.IReadOnlyDictionary": "std::collections::HashMap<K, V>",
+    "System.Collections.Generic.IReadOnlyList": "Vec<T>",
+    "System.Collections.Generic.KeyValuePair": "(K, V)",
+    "System.Collections.Generic.LinkedList": "std::collections::LinkedList<T>",
+    "System.Collections.Generic.List": "Vec<T>",
+    "System.Collections.Generic.Queue": "std::collections::VecDeque<T>",
+    "System.Collections.Generic.SortedDictionary": "std::collections::BTreeMap<K, V>",
+    "System.Collections.Generic.Stack": "Vec<T>",
+    "System.Collections.ObjectModel.ReadOnlyCollection": "Vec<T>",
+    "System.Collections.Specialized.NameValueCollection": "std::collections::HashMap<String, Vec<String>>",
+    "System.Collections.Concurrent.ConcurrentDictionary": "std::sync::RwLock<std::collections::HashMap<K, V>>",
+    "System.Collections.Concurrent.ConcurrentQueue": "std::sync::Mutex<std::collections::VecDeque<T>>",
+    "System.Collections.Concurrent.ConcurrentStack": "std::sync::Mutex<Vec<T>>",
+    "System.Action": "Box<dyn Fn() + Send + Sync>",
+    "System.Comparison": "Box<dyn Fn(&T, &T) -> std::cmp::Ordering + Send + Sync>",
+    "System.Converter": "Box<dyn Fn(TInput) -> TOutput + Send + Sync>",
+    "System.Func": "Box<dyn Fn(Args) -> Output + Send + Sync>",
+    "System.Predicate": "Box<dyn Fn(&T) -> bool + Send + Sync>",
+    "System.AsyncCallback": "Box<dyn Fn(&dyn std::any::Any) + Send + Sync>",
+    "System.IAsyncResult": "Box<dyn std::any::Any + Send + Sync>",
+    "System.ICloneable": "Clone",
+    "System.IComparable": "Ord",
+    "System.IComparable`1": "Ord",
+    "System.IConvertible": "libremetaverse_types::compat::Convertible",
+    "System.IDisposable": "libremetaverse_types::compat::Close",
+    "System.IEquatable": "Eq",
+    "System.IFormattable": "std::fmt::Display",
+    "System.ISpanFormattable": "std::fmt::Display",
+    "System.DateTime": "std::time::SystemTime",
+    "System.DateTimeOffset": "std::time::SystemTime",
+    "System.TimeSpan": "std::time::Duration",
+    "System.Guid": "uuid::Uuid",
+    "System.Uri": "url::Url",
+    "System.Version": "libremetaverse_types::compat::Version",
+    "System.Random": "libremetaverse_types::compat::RandomSource",
+    "System.Exception": "libremetaverse_types::compat::ExternalError",
+    "System.EventArgs": "()",
+    "System.EventHandler": "libremetaverse_types::compat::EventHandler<T>",
+    "System.Object": "libremetaverse_types::compat::Object",
+    "System.Type": "libremetaverse_types::compat::TypeId",
+    "System.Char": "libremetaverse_types::compat::Utf16CodeUnit",
+    "System.Decimal": "libremetaverse_types::compat::Decimal",
+    "System.Enum": "libremetaverse_types::compat::EnumValue",
+    "System.Attribute": "libremetaverse_types::compat::Attribute",
+    "System.Delegate": "libremetaverse_types::compat::Callback",
+    "System.MulticastDelegate": "libremetaverse_types::compat::Callback",
+    "System.ValueType": "libremetaverse_types::compat::Value",
+    "System.Text.Encoding": "libremetaverse_types::compat::TextEncoding",
+    "System.Text.StringBuilder": "String",
+    "System.Text.RegularExpressions.Regex": "regex::Regex",
+    "System.IO.Stream": "Box<dyn libremetaverse_types::compat::ReadWrite + Send>",
+    "System.IO.MemoryStream": "std::io::Cursor<Vec<u8>>",
+    "System.IO.TextReader": "Box<dyn std::io::BufRead + Send>",
+    "System.IO.TextWriter": "Box<dyn std::io::Write + Send>",
+    "System.IO.BinaryReader": "libremetaverse_types::compat::BinaryReader<R>",
+    "System.IO.BinaryWriter": "libremetaverse_types::compat::BinaryWriter<W>",
+    "System.IO.FileStream": "std::fs::File",
+    "System.Net.IPAddress": "std::net::IpAddr",
+    "System.Net.IPEndPoint": "std::net::SocketAddr",
+    "System.Net.EndPoint": "std::net::SocketAddr",
+    "System.Net.Http.HttpClient": "libremetaverse::http::Client",
+    "System.Net.Http.HttpResponseMessage": "libremetaverse::http::Response",
+    "System.Net.Http.HttpMethod": "libremetaverse::http::Method",
+    "System.Net.Http.Headers.AuthenticationHeaderValue": "libremetaverse::http::Authentication",
+    "System.Net.Sockets.Socket": "libremetaverse::net::Socket",
+    "System.Net.Sockets.TcpClient": "libremetaverse::net::TcpStream",
+    "System.Net.Sockets.UdpClient": "libremetaverse::net::UdpSocket",
+    "System.Threading.CancellationToken": "libremetaverse_types::compat::CancellationToken",
+    "System.Threading.Tasks.Task": "libremetaverse_types::compat::Task<T>",
+    "System.Threading.Tasks.ValueTask": "libremetaverse_types::compat::Task<T>",
+    "System.Threading.RateLimiting.RateLimiter": "libremetaverse::net::RateLimiter",
+    "System.Numerics.BigInteger": "libremetaverse_types::compat::BigInteger",
+    "System.Numerics.Complex": "libremetaverse_types::compat::Complex64",
+    "System.Tuple": "(T1, T2)",
+    "System.ValueTuple": "(T1, T2)",
+    "System.Xml.XmlNode": "libremetaverse_structured_data::xml::Node",
+    "System.Xml.XmlElement": "libremetaverse_structured_data::xml::Element",
+    "System.Xml.XmlReader": "libremetaverse_structured_data::xml::Reader<R>",
+    "System.Xml.XmlWriter": "libremetaverse_structured_data::xml::Writer<W>",
+    "System.Text.Json.JsonElement": "libremetaverse_voice_webrtc::signaling::JsonValue",
+}
+
+THIRD_PARTY_ASSEMBLY_TARGET = {
+    "CoreJ2K": ("libremetaverse-imaging", "codec"),
+    "MessagePack": ("libremetaverse", "message_pack"),
+    "Microsoft.Extensions.DependencyInjection.Abstractions": ("libremetaverse", "services"),
+    "Microsoft.Extensions.Logging.Abstractions": ("libremetaverse", "logging"),
+    "SIPSorcery": ("libremetaverse-voice-webrtc", "transport"),
+    "SIPSorceryMedia.Abstractions": ("libremetaverse-voice-webrtc", "media"),
+    "SIPSorceryMedia.SoundFlow": ("libremetaverse-voice-webrtc", "audio"),
+    "SkiaSharp": ("libremetaverse-imaging-skia", "backend"),
+    "SoundFlow.Abstracts": ("libremetaverse-voice-webrtc", "audio"),
+    "SoundFlow.Backends.MiniAudio": ("libremetaverse-voice-webrtc", "audio"),
+    "SoundFlow.Extensions.WebRtc.Apm": ("libremetaverse-voice-webrtc", "audio"),
+}
+
+VALID_MEMBER_STATUSES = {"mapped", "intentional_difference"}
+VALID_TYPE_STATUSES = {"mapped"}
+SUPPORT_TYPES = {
+    "LibreMetaverse.RLV.IBlacklistProvider": ("libremetaverse-rlv", "provider", "libremetaverse_rlv::provider::BlacklistProvider"),
+    "LibreMetaverse.RLV.IRestrictionProvider": ("libremetaverse-rlv", "provider", "libremetaverse_rlv::provider::RestrictionProvider"),
+}
+RUST_KEYWORDS = {
+    "as", "break", "const", "continue", "crate", "else", "enum", "extern", "false", "fn",
+    "for", "if", "impl", "in", "let", "loop", "match", "mod", "move", "mut", "pub", "ref",
+    "return", "self", "Self", "static", "struct", "super", "trait", "true", "type", "unsafe",
+    "use", "where", "while", "async", "await", "dyn", "abstract", "become", "box", "do", "final",
+    "macro", "override", "priv", "typeof", "unsized", "virtual", "yield", "try",
+}
+
+
+def snake(name: str) -> str:
+    name = name.lstrip("@").replace("#", "_")
+    name = re.sub(r"([A-Z]+)([A-Z][a-z])", r"\1_\2", name)
+    name = re.sub(r"([a-z0-9])([A-Z])", r"\1_\2", name).lower()
+    name = re.sub(r"[^a-z0-9_]", "_", name).strip("_") or "item"
+    if name[0].isdigit() or keyword.iskeyword(name) or name in RUST_KEYWORDS:
+        name += "_"
+    return name
+
+
+def pascal(name: str) -> str:
+    parts = re.split(r"[^A-Za-z0-9]+", name.replace("`", "_"))
+    value = "_".join(part[:1].upper() + part[1:] for part in parts if part) or "Type"
+    return value + "Type" if value in RUST_KEYWORDS else value
+
+
+def split_top_level(value: str) -> list[str]:
+    depth = 0
+    start = 0
+    parts = []
+    for index, char in enumerate(value):
+        depth += char == "<"
+        depth -= char == ">"
+        if char == "," and depth == 0:
+            parts.append(value[start:index].strip())
+            start = index + 1
+    parts.append(value[start:].strip())
+    return [part for part in parts if part]
+
+
+def type_parts(value: str) -> tuple[str, list[str], str]:
+    value = value.strip()
+    suffix = ""
+    while value.endswith("&") or value.endswith("*"):
+        suffix = value[-1] + suffix
+        value = value[:-1]
+    while array := re.search(r"(\[[,]*\])$", value):
+        suffix = array.group(1) + suffix
+        value = value[: array.start()]
+    first = value.find("<")
+    if first < 0:
+        return value, [], suffix
+    depth = 0
+    close = -1
+    for index in range(first, len(value)):
+        depth += value[index] == "<"
+        depth -= value[index] == ">"
+        if depth == 0:
+            close = index
+            break
+    if close < 0:
+        raise ValueError(f"unbalanced generic type: {value}")
+    base = value[:first] + value[close + 1 :]
+    return base, split_top_level(value[first + 1 : close]), suffix
+
+
+def substitute(template: str, arguments: list[str]) -> str:
+    names = re.findall(r"\b(?:T\d*|TKey|TValue|TInput|TOutput|Args|Output|K|V|R|W)\b", template)
+    for name, argument in zip(dict.fromkeys(names), arguments):
+        template = re.sub(rf"\b{re.escape(name)}\b", argument, template)
+    return template
+
+
+def nullable(value: str, nullability: dict | None) -> str:
+    if nullability and (nullability.get("read") == "nullable" or nullability.get("write") == "nullable"):
+        return f"Option<{value}>"
+    return value
+
+
+def assembly_module_prefix(assembly: str, namespace: str) -> list[str]:
+    roots = {
+        "LibreMetaverse": "LibreMetaverse",
+        "LibreMetaverse.Types": "LibreMetaverse",
+        "LibreMetaverse.StructuredData": "LibreMetaverse.StructuredData",
+        "LibreMetaverse.Imaging.Abstractions": "LibreMetaverse.Imaging",
+        "LibreMetaverse.Imaging.Skia": "LibreMetaverse.Imaging.Skia",
+        "LibreMetaverse.PrimMesher": "LibreMetaverse.PrimMesher",
+        "LibreMetaverse.Rendering.Simple": "LibreMetaverse.Rendering",
+        "LibreMetaverse.Rendering.MeshFoundry": "LibreMetaverse.Rendering",
+        "LibreMetaverse.LslTools": "LibreMetaverse.LslTools",
+        "LibreMetaverse.RLV": "LibreMetaverse.RLV",
+        "LibreMetaverse.Utilities": "LibreMetaverse.Utilities",
+        "LibreMetaverse.Voice.Vivox": "LibreMetaverse.Voice.Vivox",
+        "LibreMetaverse.Voice.WebRTC": "LibreMetaverse.Voice.WebRTC",
+    }
+    root = roots[assembly]
+    remainder = namespace[len(root) :].lstrip(".") if namespace.startswith(root) else namespace
+    return [snake(part) for part in remainder.split(".") if part]
+
+
+def declared_type_path(assembly: str, item: dict) -> tuple[str, str, str]:
+    crate = ASSEMBLY_CRATES[assembly]
+    modules = assembly_module_prefix(assembly, item["namespace"])
+    base, _, _ = type_parts(item["signature"])
+    tail = base[len(item["namespace"]) :].lstrip(".")
+    # Flatten nested type ownership into the type name; the containing type keeps paths unique.
+    type_name = "".join(pascal(part) for part in tail.split("."))
+    module = "::".join(modules)
+    path = "::".join([crate.replace("-", "_"), *modules, type_name])
+    return crate, module, path
+
+
+def generic_bounds_text(item: dict) -> str:
+    generics = {parameter["name"] for parameter in item.get("generic_parameters", [])}
+    mapper = Mapper({})
+    rendered = []
+    for parameter in item.get("generic_parameters", []):
+        bounds = [mapper.constraint(constraint, generics) for constraint in parameter.get("constraints", [])]
+        if parameter.get("default_constructor"):
+            bounds.append("Default")
+        rendered.append(parameter["name"] + ((": " + " + ".join(bounds)) if bounds else ""))
+    return ", ".join(rendered) or "none"
+
+
+def enum_decision(item: dict) -> str:
+    if item["kind"] != "enum":
+        return "not_applicable"
+    if any(attribute["type"] == "System.FlagsAttribute" for attribute in item.get("attributes", [])):
+        return f"bitflags<{item.get('enum_underlying_type', 'unknown')}>; retain unknown bits"
+    return f"repr<{item.get('enum_underlying_type', 'unknown')}>; preserve discriminants; Unknown(raw) only when extensible"
+
+
+def external_type_target(item: dict) -> tuple[str, str, str, str]:
+    base, arguments, _ = type_parts(item["signature"])
+    if base in PRIMITIVES:
+        return "core", "primitive", PRIMITIVES[base], "language"
+    if base == "System.Action":
+        return "core", "callback", f"Box<dyn Fn({', '.join(arguments)}) + Send + Sync>", "language"
+    if base == "System.Func":
+        output = arguments[-1] if arguments else "()"
+        return "core", "callback", f"Box<dyn Fn({', '.join(arguments[:-1])}) -> {output} + Send + Sync>", "language"
+    if base == "System.EventHandler":
+        return "libremetaverse-types", "compat", f"libremetaverse_types::compat::EventHandler<{arguments[-1] if arguments else '()'}>", "native_cross_platform_replacement"
+    if base in {"System.Tuple", "System.ValueTuple"}:
+        return "core", "tuple", "(" + ", ".join(arguments) + ("," if len(arguments) == 1 else "") + ")", "language"
+    if base == "System.Nullable" and arguments:
+        return "core", "option", f"Option<{arguments[0]}>", "language"
+    if base in {"System.Threading.Tasks.Task", "System.Threading.Tasks.ValueTask"}:
+        return "libremetaverse-types", "compat", f"libremetaverse_types::compat::Task<{arguments[0] if arguments else '()'}>", "native_cross_platform_replacement"
+    if base in STDLIB:
+        target = substitute(STDLIB[base], arguments)
+        if arguments and "<" not in target and target not in {"Ord", "Eq", "Clone", "std::fmt::Display"}:
+            target += "<" + ", ".join(arguments) + ">"
+        crate = target.split("::", 1)[0].replace("_", "-") if "::" in target else "std"
+        return crate, "", target, "stdlib_or_adopted_crate"
+    assembly = item["assembly"]["name"]
+    if assembly in THIRD_PARTY_ASSEMBLY_TARGET:
+        crate, module = THIRD_PARTY_ASSEMBLY_TARGET[assembly]
+        target = f"{crate.replace('-', '_')}::{module}::{pascal(base.rsplit('.', 1)[-1])}"
+        if arguments:
+            target += "<" + ", ".join(arguments) + ">"
+        return crate, module, target, "native_cross_platform_replacement"
+    # Remaining BCL concepts get explicit project-owned compatibility types.
+    if assembly.startswith("System.") or assembly in {"System.Private.CoreLib", "System"}:
+        target = f"libremetaverse_types::compat::{pascal(base.rsplit('.', 1)[-1])}"
+        if arguments:
+            target += "<" + ", ".join(arguments) + ">"
+        return "libremetaverse-types", "compat", target, "native_cross_platform_replacement"
+    raise ValueError(f"no reviewed external type rule for {item['doc_id']} from {assembly}")
+
+
+def render_tsv(fieldnames: list[str], rows: list[dict[str, str]]) -> str:
+    output = io.StringIO(newline="")
+    writer = csv.DictWriter(output, fieldnames=fieldnames, delimiter="\t", lineterminator="\n")
+    writer.writeheader()
+    writer.writerows(rows)
+    return output.getvalue()
+
+
+def build_type_rows(catalog: dict) -> tuple[list[dict[str, str]], dict[str, str]]:
+    rows = []
+    resolved: dict[str, str] = {}
+    for assembly in catalog["assemblies"]:
+        assembly_name = assembly["identity"]["name"]
+        for item in assembly["types"]:
+            crate, module, path = declared_type_path(assembly_name, item)
+            base, _, _ = type_parts(item["signature"])
+            if base in resolved and resolved[base] != path:
+                raise ValueError(f"ambiguous catalog type signature: {base}")
+            resolved[base] = path
+            rows.append({
+                "csharp_type_id": item["doc_id"], "csharp_signature": item["signature"],
+                "source_assembly": assembly_name, "source_kind": item["kind"], "rust_crate": crate,
+                "rust_module": module, "rust_path": path, "mapping_decision": "native_metacrate_type",
+                "generic_bounds": generic_bounds_text(item),
+                "inheritance_mapping": "traits_and_composition: " + ", ".join(filter(None, [item.get("base_type"), *item.get("interfaces", [])])) if item.get("base_type") or item.get("interfaces") else "none",
+                "enum_mapping": enum_decision(item),
+                "status": "mapped", "notes": "nested types are flattened" if "." in type_parts(item["signature"])[0][len(item["namespace"]) + 1 :] else "none",
+            })
+    for item in catalog["external_types"]:
+        crate, module, target, decision = external_type_target(item)
+        base, _, _ = type_parts(item["signature"])
+        if base in PRIMITIVES:
+            resolved[base] = PRIMITIVES[base]
+        elif base in STDLIB:
+            resolved[base] = STDLIB[base]
+        elif item["assembly"]["name"] in THIRD_PARTY_ASSEMBLY_TARGET:
+            resolved[base] = f"{crate.replace('-', '_')}::{module}::{pascal(base.rsplit('.', 1)[-1])}"
+        else:
+            resolved.setdefault(base, target.split("<", 1)[0])
+        rows.append({
+            "csharp_type_id": item["doc_id"], "csharp_signature": item["signature"],
+            "source_assembly": item["assembly"]["name"], "source_kind": item["kind"],
+            "rust_crate": crate, "rust_module": module, "rust_path": target,
+            "mapping_decision": decision, "status": "mapped",
+            "generic_bounds": "not_applicable", "inheritance_mapping": "not_applicable", "enum_mapping": "not_applicable",
+            "notes": "external member surface is not copied",
+        })
+    for signature, (crate, module, target) in SUPPORT_TYPES.items():
+        resolved[signature] = target
+        rows.append({
+            "csharp_type_id": f"T:{signature}", "csharp_signature": signature,
+            "source_assembly": "LibreMetaverse.RLV", "source_kind": "referenced_support_trait",
+            "rust_crate": crate, "rust_module": module, "rust_path": target,
+            "mapping_decision": "native_metacrate_support_trait", "status": "mapped",
+            "generic_bounds": "none", "inheritance_mapping": "native_trait", "enum_mapping": "not_applicable",
+            "notes": "referenced by a public base/interface signature but absent from the public type table",
+        })
+    rows.sort(key=lambda row: row["csharp_type_id"])
+    return rows, resolved
+
+
+class Mapper:
+    def __init__(self, resolved: dict[str, str]):
+        self.resolved = resolved
+
+    def type(self, value: str, nullability: dict | None = None, generics: set[str] | None = None) -> str:
+        base, arguments, suffix = type_parts(value)
+        generics = generics or set()
+        child_nullability = (nullability or {}).get("generic_arguments", [])
+        mapped_arguments = [
+            self.type(argument, child_nullability[index] if index < len(child_nullability) else None, generics)
+            for index, argument in enumerate(arguments)
+        ]
+        if base == "System.Action":
+            parameters = ", ".join(mapped_arguments)
+            target = f"Box<dyn Fn({parameters}) + Send + Sync>"
+        elif base == "System.Func":
+            output = mapped_arguments[-1] if mapped_arguments else "()"
+            parameters = ", ".join(mapped_arguments[:-1])
+            target = f"Box<dyn Fn({parameters}) -> {output} + Send + Sync>"
+        elif base == "System.EventHandler":
+            target = f"libremetaverse_types::compat::EventHandler<{mapped_arguments[-1] if mapped_arguments else '()'}>"
+        elif base in {"System.Tuple", "System.ValueTuple"}:
+            target = "(" + ", ".join(mapped_arguments) + ("," if len(mapped_arguments) == 1 else "") + ")"
+        elif base == "System.Nullable" and mapped_arguments:
+            target = f"Option<{mapped_arguments[0]}>"
+        elif base in {"System.Threading.Tasks.Task", "System.Threading.Tasks.ValueTask"}:
+            target = f"libremetaverse_types::compat::Task<{mapped_arguments[0] if mapped_arguments else '()'}>"
+        else:
+            target = None
+        if base in generics or ("." not in base and base.startswith("T")):
+            target = base
+        elif target is None:
+            target = self.resolved.get(base)
+            if target is None:
+                raise ValueError(f"unresolved referenced type: {value} (base {base})")
+        if mapped_arguments and base not in {
+            "System.Action", "System.Func", "System.EventHandler", "System.Nullable", "System.Tuple",
+            "System.ValueTuple", "System.Threading.Tasks.Task", "System.Threading.Tasks.ValueTask",
+        }:
+            target = substitute(target, mapped_arguments)
+            if "<" not in target and target not in {"Ord", "Eq", "Clone", "std::fmt::Display"}:
+                target += "<" + ", ".join(mapped_arguments) + ">"
+        for _ in re.findall(r"\[[,]*\]", suffix):
+            target = f"Vec<{target}>"
+        if "*" in suffix:
+            target = f"libremetaverse_types::compat::Pointer<{target}>"
+        return nullable(target, nullability)
+
+    def constraint(self, value: str, generics: set[str]) -> str:
+        base, arguments, _ = type_parts(value)
+        if base == "System.IDisposable":
+            return "libremetaverse_types::compat::Close"
+        if base == "System.Collections.Generic.ICollection" and arguments:
+            return f"libremetaverse_types::compat::Collection<{self.type(arguments[0], None, generics)}>"
+        raise ValueError(f"no Rust generic-bound rule for {value}")
+
+
+def generic_names(item: dict, owner: dict) -> set[str]:
+    names = set()
+    for source in (owner.get("generic_parameters", []), item.get("generic_parameters", [])):
+        for parameter in source:
+            names.add(parameter["name"] if isinstance(parameter, dict) else str(parameter))
+    return names
+
+
+def method_receiver(owner: dict, item: dict) -> tuple[str, str]:
+    if item.get("static") or item["kind"] == "constructor":
+        return "", "none"
+    observers = ("Get", "TryGet", "Find", "Contains", "Has", "Is", "Can", "To", "Equals", "Compare")
+    if owner["kind"] == "struct" and not item["name"].startswith(observers) and not item["name"].startswith("op_"):
+        return "&mut self", "mutable_self"
+    return "&self", "shared_self"
+
+
+def map_parameter(mapper: Mapper, parameter: dict, generics: set[str]) -> tuple[str, str]:
+    name = snake(parameter["name"])
+    rust_type = mapper.type(parameter["type"], parameter.get("nullability"), generics)
+    passing = parameter.get("passing", "value")
+    ownership = "owned"
+    if passing == "out":
+        return "mutable_output", f"{name}: &mut {rust_type}"
+    if passing in {"ref", "in"}:
+        mutable = "mut " if passing == "ref" else ""
+        return ("mutable_borrow" if passing == "ref" else "shared_borrow"), f"{name}: &{mutable}{rust_type}"
+    if parameter.get("optional"):
+        rust_type = rust_type if rust_type.startswith("Option<") else f"Option<{rust_type}>"
+        ownership = "optional_owned"
+    return ownership, f"{name}: {rust_type}"
+
+
+def member_base_name(item: dict) -> str:
+    if item["kind"] == "enum_value":
+        return pascal(item["name"])
+    if item["kind"] == "constant" or (item["kind"] == "field" and item.get("static")):
+        return snake(item["name"]).upper()
+    if item["kind"] == "constructor":
+        return "new"
+    operators = {
+        "op_Addition": "add", "op_Subtraction": "sub", "op_Multiply": "mul", "op_Division": "div",
+        "op_Equality": "eq", "op_Inequality": "ne", "op_Implicit": "from", "op_Explicit": "try_from",
+        "op_UnaryNegation": "neg", "op_LessThan": "lt", "op_GreaterThan": "gt",
+        "op_LessThanOrEqual": "le", "op_GreaterThanOrEqual": "ge", "op_Modulus": "rem",
+        "op_BitwiseAnd": "bitand", "op_BitwiseOr": "bitor", "op_ExclusiveOr": "bitxor",
+        "op_LeftShift": "shl", "op_RightShift": "shr", "op_OnesComplement": "not",
+    }
+    return operators.get(item["name"], snake(item["name"].removesuffix("Async")))
+
+
+def member_signature(mapper: Mapper, owner: dict, item: dict, rust_name: str) -> tuple[str, str, str, str, str]:
+    generics = generic_names(item, owner)
+    mapped_parameters = [map_parameter(mapper, parameter, generics) for parameter in item.get("parameters", [])]
+    own = [value[0] for value in mapped_parameters]
+    parameters = ", ".join(value[1] for value in mapped_parameters)
+    kind = item["kind"]
+    asyncness = "sync"
+    error_model = "infallible_placeholder"
+    if kind in {"field", "constant", "enum_value"}:
+        value_type = mapper.type(item["type"], item.get("nullability"), generics)
+        if kind == "enum_value":
+            signature = f"{rust_name}: {value_type}"
+        elif kind == "constant":
+            signature = f"pub const {rust_name}: {value_type}"
+        elif item.get("static"):
+            signature = f"pub static {rust_name}: {value_type}"
+        else:
+            signature = f"pub {rust_name}: {value_type}"
+        return signature, "owned_value", asyncness, "none", "direct"
+    if kind in {"property", "indexer"}:
+        value_type = mapper.type(item["type"], item.get("nullability"), generics)
+        accessors = {accessor["kind"] for accessor in item.get("accessors", [])}
+        pieces = []
+        if "get" in accessors:
+            getter = parameters if item.get("static") else ", ".join(filter(None, ["&self", parameters]))
+            pieces.append(f"pub fn {rust_name}({getter}) -> {value_type}")
+        if "set" in accessors:
+            setter = ", ".join(filter(None, ["" if item.get("static") else "&mut self", parameters, f"value: {value_type}"]))
+            pieces.append(f"pub fn set_{rust_name}({setter})")
+        self_ownership = [] if item.get("static") else (["shared_self"] if accessors == {"get"} else ["shared_or_mutable_self"])
+        return " ; ".join(pieces), ",".join([*self_ownership, *own]) or "none", asyncness, error_model, "accessor_methods"
+    if kind == "event":
+        event_type = mapper.type(item["type"], item.get("nullability"), generics)
+        return f"pub fn subscribe_{rust_name}(&self, handler: {event_type}) -> Subscription", "stored_callback", asyncness, error_model, "subscription_guard"
+    self_argument, self_ownership = method_receiver(owner, item)
+    arguments = ", ".join(filter(None, [self_argument, parameters]))
+    ownership = ",".join(([self_ownership] if self_ownership != "none" else []) + own) or "none"
+    raw_return = item.get("type", "System.Void")
+    return_type = mapper.type(raw_return, item.get("nullability"), generics)
+    if raw_return.startswith(("System.Threading.Tasks.Task", "System.Threading.Tasks.ValueTask")):
+        asyncness = "async"
+        base, task_arguments, _ = type_parts(raw_return)
+        child = item.get("nullability", {}).get("generic_arguments", [])
+        return_type = mapper.type(task_arguments[0], child[0] if child else None, generics) if task_arguments else "()"
+        error_model = "Result<_, crate::Error>"
+    elif kind in {"method", "constructor"} and not (
+        item["name"].startswith("Try")
+        or item["name"] in {"Equals", "GetHashCode", "ToString"}
+        or item["name"].startswith("op_")
+    ):
+        error_model = "Result<_, crate::Error>"
+    if kind == "constructor":
+        return_type = "Self"
+    if error_model.startswith("Result"):
+        return_type = f"Result<{return_type}, crate::Error>"
+    generic_declarations = []
+    for parameter in item.get("generic_parameters", []):
+        bounds = [mapper.constraint(constraint, generics) for constraint in parameter.get("constraints", [])]
+        if parameter.get("default_constructor"):
+            bounds.append("Default")
+        generic_declarations.append(parameter["name"] + ((": " + " + ".join(bounds)) if bounds else ""))
+    generic_suffix = "<" + ", ".join(generic_declarations) + ">" if generic_declarations else ""
+    prefix = "pub async fn" if asyncness == "async" else "pub fn"
+    return f"{prefix} {rust_name}{generic_suffix}({arguments}) -> {return_type}", ownership, asyncness, error_model, "method"
+
+
+def csharp_signature(owner: dict, item: dict) -> str:
+    parameters = ", ".join(
+        " ".join(filter(None, [parameter.get("passing") if parameter.get("passing") != "value" else "", parameter["type"], parameter["name"]]))
+        + (" = default" if parameter.get("optional") else "")
+        for parameter in item.get("parameters", [])
+    )
+    if item["kind"] == "constructor":
+        return f"{owner['signature']}({parameters})"
+    if item["kind"] in {"method"}:
+        return f"{item.get('type', 'System.Void')} {owner['signature']}.{item['name']}({parameters})"
+    return f"{item.get('type', 'System.Void')} {owner['signature']}.{item['name']}"
+
+
+def build_member_rows(catalog: dict, mapper: Mapper) -> list[dict[str, str]]:
+    rows = []
+    for assembly in catalog["assemblies"]:
+        assembly_name = assembly["identity"]["name"]
+        crate = ASSEMBLY_CRATES[assembly_name]
+        for owner in assembly["types"]:
+            _, module, owner_path = declared_type_path(assembly_name, owner)
+            groups = Counter(member_base_name(member) for member in owner["members"])
+            used = set()
+            for item in owner["members"]:
+                base_name = member_base_name(item)
+                rust_name = base_name
+                decision = "direct_snake_case"
+                if groups[base_name] > 1:
+                    suffixes = []
+                    for parameter in item.get("parameters", []):
+                        base, _, _ = type_parts(parameter["type"])
+                        suffixes.append(snake(base.rsplit(".", 1)[-1]))
+                    suffix = "_".join(suffixes) or item["kind"]
+                    rust_name = f"{base_name}_with_{suffix}"
+                    decision = "descriptive_overload_name"
+                destination = f"{owner_path}::{rust_name}"
+                if destination in used:
+                    digest = hashlib.sha256(item["doc_id"].encode()).hexdigest()[:8]
+                    rust_name += f"_{digest}"
+                    destination = f"{owner_path}::{rust_name}"
+                    decision = "descriptive_overload_name_with_stable_id"
+                used.add(destination)
+                signature, ownership, asyncness, error_model, mapping_kind = member_signature(mapper, owner, item, rust_name)
+                status = "intentional_difference" if item["name"] in {"BeginInvoke", "EndInvoke"} else "mapped"
+                if status == "intentional_difference":
+                    mapping_kind = "native_callback_replaces_delegate_apm"
+                rows.append({
+                    "csharp_id": item["doc_id"], "csharp_kind": item["kind"],
+                    "csharp_signature": csharp_signature(owner, item), "rust_crate": crate,
+                    "rust_module": module, "rust_item_path": destination, "rust_signature": signature,
+                    "ownership": ownership, "asyncness": asyncness, "error_model": error_model,
+                    "overload_decision": decision, "mapping_kind": mapping_kind, "status": status,
+                })
+    rows.sort(key=lambda row: row["csharp_id"])
+    return rows
+
+
+def validate(catalog: dict, type_rows: list[dict[str, str]], member_rows: list[dict[str, str]], mapper: Mapper) -> None:
+    def unique(rows: list[dict[str, str]], field: str) -> None:
+        duplicates = [value for value, count in Counter(row[field] for row in rows).items() if count > 1]
+        if duplicates:
+            raise ValueError(f"duplicate {field}: {duplicates[:3]}")
+
+    unique(type_rows, "csharp_type_id")
+    unique(member_rows, "csharp_id")
+    unique(member_rows, "rust_item_path")
+    for row in type_rows:
+        for field in ("csharp_type_id", "csharp_signature", "source_assembly", "source_kind", "rust_crate", "rust_path", "mapping_decision", "generic_bounds", "inheritance_mapping", "enum_mapping", "status"):
+            if not row[field]:
+                raise ValueError(f"empty required type field {field}: {row['csharp_type_id']}")
+    for row in member_rows:
+        for field in row:
+            if not row[field] and field != "rust_module":
+                raise ValueError(f"empty required member field {field}: {row['csharp_id']}")
+        signature = row["rust_signature"].replace("->", "")
+        for opening, closing in (("(", ")"), ("<", ">")):
+            if signature.count(opening) != signature.count(closing):
+                raise ValueError(f"unbalanced Rust signature: {row['csharp_id']}")
+    if {row["status"] for row in type_rows} - VALID_TYPE_STATUSES:
+        raise ValueError("invalid type mapping status")
+    if {row["status"] for row in member_rows} - VALID_MEMBER_STATUSES:
+        raise ValueError("invalid member mapping status")
+    catalog_ids = {member["doc_id"] for assembly in catalog["assemblies"] for item in assembly["types"] for member in item["members"]}
+    mapped_ids = {row["csharp_id"] for row in member_rows}
+    if catalog_ids != mapped_ids:
+        raise ValueError(f"catalog/mapping ID mismatch: missing={len(catalog_ids - mapped_ids)}, stale={len(mapped_ids - catalog_ids)}")
+    external_ids = {item["doc_id"] for item in catalog["external_types"]}
+    mapped_type_ids = {row["csharp_type_id"] for row in type_rows}
+    if not external_ids <= mapped_type_ids:
+        raise ValueError(f"unresolved external types: {sorted(external_ids - mapped_type_ids)[:3]}")
+    catalog_type_ids = {item["doc_id"] for assembly in catalog["assemblies"] for item in assembly["types"]}
+    expected_type_ids = catalog_type_ids | external_ids | {f"T:{name}" for name in SUPPORT_TYPES}
+    if mapped_type_ids != expected_type_ids:
+        raise ValueError(f"catalog/type mapping ID mismatch: missing={len(expected_type_ids - mapped_type_ids)}, stale={len(mapped_type_ids - expected_type_ids)}")
+    represented = {row["rust_crate"] for row in member_rows}
+    missing_assemblies = {crate for crate in ASSEMBLY_CRATES.values() if crate not in represented}
+    if missing_assemblies:
+        raise ValueError(f"assemblies without representative mappings: {sorted(missing_assemblies)}")
+    forbidden = re.compile(r"macos|darwin|cocoa|appkit", re.IGNORECASE)
+    for row in [*type_rows, *member_rows]:
+        if forbidden.search("\t".join(row.values())):
+            raise ValueError(f"platform-specific mapping is prohibited: {row}")
+    # Re-walk every public type reference. This intentionally includes bases and interfaces.
+    for assembly in catalog["assemblies"]:
+        for owner in assembly["types"]:
+            owner_generics = generic_names({}, owner)
+            for parameter in owner.get("generic_parameters", []):
+                for constraint in parameter.get("constraints", []):
+                    mapper.constraint(constraint, owner_generics)
+            for value in filter(None, [owner.get("base_type"), *owner.get("interfaces", [])]):
+                mapper.type(value, None, owner_generics)
+            if owner.get("delegate_signature"):
+                delegate = owner["delegate_signature"]
+                mapper.type(delegate["type"], delegate.get("nullability"), owner_generics)
+                for parameter in delegate.get("parameters", []):
+                    mapper.type(parameter["type"], parameter.get("nullability"), owner_generics)
+            for item in owner["members"]:
+                generics = generic_names(item, owner)
+                for parameter in item.get("generic_parameters", []):
+                    for constraint in parameter.get("constraints", []):
+                        mapper.constraint(constraint, generics)
+                for value in filter(None, [item.get("type"), item.get("return_type")]):
+                    mapper.type(value, item.get("nullability") or item.get("return_nullability"), generics)
+                for parameter in item.get("parameters", []):
+                    mapper.type(parameter["type"], parameter.get("nullability"), generics)
+
+
+def coverage_report(catalog: dict, type_rows: list[dict[str, str]], member_rows: list[dict[str, str]]) -> str:
+    by_crate = Counter(row["rust_crate"] for row in member_rows)
+    representatives = {}
+    for row in member_rows:
+        representatives.setdefault(row["rust_crate"], row)
+    external = [row for row in type_rows if not row["source_assembly"].startswith("LibreMetaverse")]
+    lines = [
+        "# Rust mapping coverage", "", "Generated by `python3 tools/generate_rust_mapping.py`; do not edit by hand.", "",
+        "## Gate", "",
+        f"- C# public types mapped: **{sum(row['mapping_decision'] == 'native_metacrate_type' for row in type_rows):,} / {catalog['summary']['public_type_count']:,} (100%)**",
+        f"- C# public members mapped: **{len(member_rows):,} / {catalog['summary']['public_member_count']:,} (100%)**",
+        f"- External signature types resolved: **{len(external):,} / {len(catalog['external_types']):,} (100%)**",
+        "- Duplicate C# IDs: **0**", "- Duplicate Rust destinations: **0**", "- Stale or missing catalog IDs: **0**",
+        "- Unresolved referenced types: **0**", "- Platform-specific mappings: **0**", "",
+        "## Assembly representatives", "", "| Assembly | Rust crate | Members | Representative mapping |", "|---|---|---:|---|",
+    ]
+    for assembly in catalog["assemblies"]:
+        name = assembly["identity"]["name"]
+        crate = ASSEMBLY_CRATES[name]
+        row = representatives[crate]
+        lines.append(f"| `{name}` | `{crate}` | {by_crate[crate]:,} | `{row['csharp_id']}` -> `{row['rust_item_path']}` |")
+    lines += ["", "## External replacement decisions", "", "External member APIs are not copied. Each signature type resolves to Rust core/std, an adopted cross-platform crate, or a project-owned native compatibility type.", "", "| Decision | Types |", "|---|---:|"]
+    for decision, count in sorted(Counter(row["mapping_decision"] for row in external).items()):
+        lines.append(f"| `{decision}` | {count:,} |")
+    members = [member for assembly in catalog["assemblies"] for item in assembly["types"] for member in item["members"]]
+    parameters = [parameter for member in members for parameter in member.get("parameters", [])]
+    types = [item for assembly in catalog["assemblies"] for item in assembly["types"]]
+    flags = sum(
+        any(attribute["type"] == "System.FlagsAttribute" for attribute in item.get("attributes", []))
+        for item in types if item["kind"] == "enum"
+    )
+    lines += [
+        "", "## Schema decisions exercised", "",
+        f"- Properties/indexers/events: **{sum(m['kind'] == 'property' for m in members):,} / {sum(m['kind'] == 'indexer' for m in members):,} / {sum(m['kind'] == 'event' for m in members):,}**",
+        f"- Delegates and flags enums: **{sum(t['kind'] == 'delegate' for t in types):,} / {flags:,}**",
+        f"- Optional/ref/out/in parameters: **{sum(p.get('optional') for p in parameters):,} / {sum(p.get('passing') == 'ref' for p in parameters):,} / {sum(p.get('passing') == 'out' for p in parameters):,} / {sum(p.get('passing') == 'in' for p in parameters):,}**",
+        f"- Async Rust signatures: **{sum(row['asyncness'] == 'async' for row in member_rows):,}**",
+        f"- Descriptively renamed overloads: **{sum(row['overload_decision'] != 'direct_snake_case' for row in member_rows):,}**",
+        f"- Explicit CLR delegate APM differences: **{sum(row['status'] == 'intentional_difference' for row in member_rows):,}**",
+        "", "Run `python3 tools/generate_rust_mapping.py --check` to regenerate in memory and enforce the complete gate.", "",
+    ]
+    return "\n".join(lines)
+
+
+def generate() -> dict[Path, str]:
+    catalog = json.loads(CATALOG.read_text())
+    type_rows, resolved = build_type_rows(catalog)
+    mapper = Mapper(resolved)
+    member_rows = build_member_rows(catalog, mapper)
+    validate(catalog, type_rows, member_rows, mapper)
+    type_fields = ["csharp_type_id", "csharp_signature", "source_assembly", "source_kind", "rust_crate", "rust_module", "rust_path", "mapping_decision", "generic_bounds", "inheritance_mapping", "enum_mapping", "status", "notes"]
+    member_fields = ["csharp_id", "csharp_kind", "csharp_signature", "rust_crate", "rust_module", "rust_item_path", "rust_signature", "ownership", "asyncness", "error_model", "overload_decision", "mapping_kind", "status"]
+    return {
+        TYPE_LEDGER: render_tsv(type_fields, type_rows),
+        MEMBER_LEDGER: render_tsv(member_fields, member_rows),
+        COVERAGE: coverage_report(catalog, type_rows, member_rows),
+    }
+
+
+def self_check() -> None:
+    assert split_top_level("A<B, C<D, E>>, F") == ["A<B, C<D, E>>", "F"]
+    assert type_parts("A<B<C>, D>.Nested[]") == ("A.Nested", ["B<C>", "D"], "[]")
+    assert snake("HTTPRequest2") == "http_request2"
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--check", action="store_true", help="fail if committed ledgers differ")
+    args = parser.parse_args()
+    self_check()
+    outputs = generate()
+    if args.check:
+        stale = [str(path.relative_to(ROOT)) for path, value in outputs.items() if not path.exists() or path.read_text() != value]
+        if stale:
+            raise SystemExit("stale generated mapping files: " + ", ".join(stale))
+    else:
+        for path, value in outputs.items():
+            path.write_text(value)
+        print("generated " + ", ".join(str(path.relative_to(ROOT)) for path in outputs))
+
+
+if __name__ == "__main__":
+    main()