Polish tool results for chat hosts and fix compressed-body truncation

[markmnl]

Rebased onto main after #11 merged.

Fixes from a user-agent session in a chat host against a hosted deployment.

Bug fix

• Compressed bodies were truncated. For a deflate-compressed message, size is the compressed wire size, while short_text previews the decoded body. shortTextIsComplete took the preview as the whole body whenever the body compressed to less than the preview cap. For example, an 807-byte body that compressed to 474 bytes came back as its first 768 bytes with body_truncated: false. Previews of deflate messages are now never treated as complete. get_message.body_bytes and the new per-message get_thread body_bytes report the decoded length. Thread truncation notes use the decoded length too. This affects get_message, the thread pid walk, wait_for_message bodies and the message resource.

Results in chat hosts

• untrusted_content_notice is added to structured results that carry other parties' words, since hosts may show structuredContent instead of the text. wait_for_message and get_thread get a next step, and get_attachment_download_url gets a fallback.
• wait_for_message:
  • Skipped entries add from, and reactions also add emoji and reaction_to. Skipped reactions are listed in the text.
  • Adds thread_topic, taken from the thread lookup it already makes.
  • The description now says that a timeout's after_id is the inbox high-water mark ("0" only for an empty inbox), and that each wait is a model turn.
• get_thread adds thread_topic. list_messages and list_sent make no extra round trips because the API returns no root topic there.
• add_recipients takes recipients. add_to remains as a deprecated alias: pass exactly one of the two.
• Attachment types are now consistent. The Web API stores application/octet-stream on upload, but its download route infers the type from the extension. A missing or generic type is now inferred from the filename. type is added to list items, get_message, send results and download links.
• delivery_status now describes response codes correctly: 200 means accepted, other fmsg codes are rejections, and null means not recorded. It adds code_meaning. Negative host-local codes now count as pending.
• whoami:
  • transport is now stdio or streamable-http (was http).
  • The text no longer states the token expiry; token_expires_at stays in the structured result, described as internal.
  • directory_names is omitted when empty.
• resolve_address describes only the resolution steps the operator configured.
• List items add reaction. Hidden reactions are never counted as unread, and mark_read accepts listed reactions.
• Descriptions and errors mention save_attachment and get_attachment_download_url only where those tools are registered.
• The server instructions now state neutrally that other fmsg tools or local credentials may act as a different address, instead of telling the model not to use them.

Graceful shutdown

• On SIGINT/SIGTERM or HttpServerHandle.close(), an in-flight wait_for_message returns at once with status interrupted. The result carries the caller's after_id and the next step: call again with the same after_id; no messages are lost. Previously the wait hung through a restart until the client's own timeout.
• New requests get 503 with Retry-After. Other in-flight requests get a 5-second grace period, then a 503.
• The process exits within a bounded time, and a second signal exits immediately.
• Tests cover: the wait engine, close() over HTTP (the interrupted result arrives promptly), a stalled request getting 503 after the grace period, and a real child process on SIGTERM (interrupted result, exit 0 in under 3 s).

Compatibility

• Tool names are unchanged and new fields are additive.
• whoami.transport changes from http to streamable-http.
• add_recipients input is now recipients; add_to is still accepted.

Tests

• New vitest coverage for: compressed messages whose short_text is the 768-byte prefix (client and tools), the structured notice and next fields, skipped reaction details, the add_to alias, attachment types, thread_topic, the timeout high-water mark, whoami text and directory, hidden-reaction unread counts, delivery codes, and titles/annotations for every tool.
• typecheck, build and 180 tests pass.

🤖 Generated with Claude Code