[angel-manuel]

Why

A Slack approval on prod (Reveni) was titled Post Slack message "…" to C0123…, even though services/slack.yaml already declares a conversations.info resolver on channel, and the existing test passes against the fake. The HTTP display resolver drops every failure without logging anything. Slack also reports its own failures in-band (200 {"ok": false, "error": "missing_scope" | "channel_not_found"}), so there was nothing on prod to diagnose from.

Likely causes, not confirmed (prod isn't reachable from the agent env):

• the connection or BYOC app lacks channels:read / groups:read;
• the target was a private channel or a DM / user ID, which chat.postMessage accepts but conversations.info can't name.

What

• Resolver misses are logged (services/param_resolver.rs). HTTP display resolvers now log three cases: transport errors and error statuses at warn, and empty projections at info. Each line carries the template get path, the param name and the upstream's short top-level error code. The substituted URL and the argument are never logged. The MCP path already did this. No behaviour change: misses still fall back to the raw ID.
• slack.yaml
  • Channels render as '#general' (display: '#{channel.name}').
  • get_thread_replies gains the channel resolver.
  • get_user gains a users.info resolver: Alice Liddell (@alice).
• Tests (tests/slack.rs)
  • The approval title (action_description) names #general.
  • An unresolvable channel still gates and falls back to the raw ID.
  • Read audit rows carry the resolved channel and user names.
  • New unit test for the error-code filter.

Follow-up

• Reveni: check that their Slack connection's granted scopes include channels:read and groups:read. If they don't, a reconnect fixes public and private channels. Once this ships, Cloud Logging will show Slack's exact error code for the next miss.
• DMs addressed by user ID still show the raw ID. Naming them as @alice needs a resolver fallback chain, and the engine allows only one target per param today.

Test plan

• cargo nextest run -p overslash-api -E 'test(/slack|upstream_error_code/)': 12/12 pass
• pre-commit hook (fmt, clippy, line-count gate)
• CI

No screenshots: no dashboard change. The title string is asserted in tests.

🤖 Generated with Claude Code

[vercel]

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Project	Deployment	Actions	Updated
overslash	Ready	Preview	Oct 28, 2026 12:17pm UTC

[github-actions]

Code diff size

+53 / −3 across 1 file (net +50)

Area	Files	Added	Removed	Net
overslash-api	1	+53	−3	+50

_{Source files under src/ only (.cjs, .go, .js, .jsx, .mjs, .py, .rs, .svelte, .ts, .tsx); test files and inline #[cfg(test)] modules excluded. 3 other changed files not counted.}

[codecov]

Codecov Report

❌ Patch coverage is 82.35294% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...rates/overslash-api/src/services/param_resolver.rs	82.35%	6 Missing ⚠️

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