feat(gateway): GatewayPolicy and declared adapter capabilities

[Moikapy]

Part of #144. This is the second #144 PR, covering section A's items 2 and 3 in the minimal scope agreed for this PR: a Policy object, plus a reply-length capability. There are no streaming or client-tool flags until something can use them.

Changes

• GatewayPolicy (src/gateway/access.ts):
  • create_gateway_policy(config) returns { tools_enabled, allows(platform, chat_id, user_id) }. It wraps the existing allowlist and toolset rules, so behavior is unchanged.
  • The runner builds the policy once and uses it for both the agent's toolset and the bus.
  • GatewayBus takes an optional policy, defaulting to the one built from config, and checks senders through it. Per-chat profiles can extend this later.
• Adapter capabilities (src/gateway/types.ts):
  • PlatformAdapter now declares capabilities: { kind: "text", max_reply_chars? }.
  • Telegram declares 4096 and Twitch 450, both from their existing constants. Discord declares 2000, which replaces a bare 2000 in its send loop. The webhook is uncapped.
  • Idle adapters keep their capabilities: create_idle_adapter takes them as a third argument.
  • The runner logs each adapter's capabilities at start.
• Docs and CHANGELOG: docs/architecture/extending.md updated (the PlatformAdapter contract, the policy, and the idle-adapter call); the CHANGELOG notes the breaking change for custom adapters.

Breaking for custom adapters

PlatformAdapter now requires capabilities, and create_idle_adapter needs the new third argument. All built-in adapters are updated.

Tests

• create_gateway_policy: the default toolset, and allowlist decisions for webhook (always allowed) and Discord/Telegram (default deny unless listed).
• A deny-all policy passed into the bus refuses the sender without running the agent.
• Every adapter declares the expected capabilities, including when it's idle with no token.
• Mutation check: I made the bus ignore the injected policy, and separately removed Discord's cap; each change made a test fail.

Checks

• tsc --noEmit: clean.
• vitest: 709/711 pass. The two failures happen only in this container: serve_transport "accepts ::1 clients" (no IPv6) and tools_review_shouldfix S-6 (process-group zombies).
• vitepress build docs: passes.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LHQAfXHofy6QkAgmfmJava

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Generated by Claude Code

[cursor]

PR #178 — Risk: HIGH (gateway sender allowlists and gateway.tools_enabled now go through GatewayPolicy: create_gateway_policy wraps check_gateway_sender and gateway_tools_enabled, the runner copies policy.tools_enabled onto the agent, and the bus checks policy.allows. Defaults stay fail-closed. PlatformAdapter now requires capabilities, and create_idle_adapter takes that as a third argument.)

Findings: Critical 0 / Warning 0 / Suggestion 0
Regressions of settled findings: none
Not reviewed: none
Action: escalated to @Moikapy
Log: 2026-10-05T14:38:04Z COMMENT, label needs-review, not merged. Same allowlist and toolset functions as before (DEFAULT_GATEWAY_TOOLS_ENABLED unless gateway.tools_enabled is set; telegram/discord/twitch still default-deny; webhook still allowed). Reply caps match the declared capabilities (telegram 4096, discord 2000, twitch 450, webhook uncapped). CI green: typecheck_and_test (20), typecheck_and_test (22), ossuary, wiki_lint, AccessLint. Auto-merge was off. Head commit author is claude, not @Moikapy. Static review only.

  

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