perf(edge-worker): load only essential MCP tools at session start to cut Linear startup latency - #1369
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perf(edge-worker): load only essential MCP tools at session start to cut Linear startup latency#1369TropicalDog17 wants to merge 2 commits into
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…-startup latency The official Linear MCP registers ~50 verbose tools whose combined descriptions alone exceed the Claude Agent SDK's ~10%-of-context threshold, silently enabling MCP tool-search auto mode. That deferred every MCP tool — including Cyrus's own local ones — behind an on-demand ToolSearch, so turn 1 stalled on remote round-trips before the agent could act on the issue. Mark the small, local cyrus-tools and cyrus-docs servers alwaysLoad so they're exempt from the auto-defer bucket, while leaving the large remote Linear catalog deferred (its 50 tools would otherwise bloat turn-1 context; the issue essentials are already injected into the prompt).
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Hi can you review for me @Connoropolous |
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…ream gh pr create defaults a fork's PR to the upstream parent repo, which silently opened PRs on cyrusagents/cyrus (e.g. cyrusagents#1376, cyrusagents#1369). Derive the target from origin via --repo/--head so the PR always lands on the fork. Claude-Session: https://claude.ai/code/session_01Y7j2xZhmHbNhMRq6665PXy
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…ream (#50) gh pr create defaults a fork's PR to the upstream parent repo, which silently opened PRs on cyrusagents/cyrus (e.g. cyrusagents#1376, cyrusagents#1369). Derive the target from origin via --repo/--head so the PR always lands on the fork. Claude-Session: https://claude.ai/code/session_01Y7j2xZhmHbNhMRq6665PXy Co-authored-by: tropicaldog17 <tropicaldog17aa@gmail.com>
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have you verified that this has the intended effect? |
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Problem
When a session starts, the agent often spends close to a minute running tool-search round-trips against Linear's remote MCP server before it can read or update the issue — a visible stall at the top of every session.
Root cause: the official Linear MCP (
mcp.linear.app) registers ~50 verbose tools. Their combined tool descriptions on their own push past the Claude Agent SDK's ~10%-of-context threshold, which silently flips the SDK into MCP tool-search auto mode. In that mode every MCP tool — including Cyrus's own local ones — is deferred behind an on-demandToolSearch. Because the Linear server is remote, discovering those deferred schemas costs real network round-trips, so turn 1 stalls before the agent can do anything with the issue.Fix
Load only the essential, local tools into turn-1 context; defer the large remote catalog.
cyrus-tools,cyrus-docs) withalwaysLoad: true, exempting them from the auto-defer bucket. These are the tools Cyrus's workflow actually depends on (agent-session/feedback management, file uploads, issue relations, docs search) and they're served locally, so there's no round-trip cost and negligible context.linearserver deferred (noalwaysLoad). Its ~50 tools would otherwise bloat turn-1 context, and the issue essentials the agent needs on turn 1 — title, description, state, priority, URL, and comment threads — are already injected into the prompt by the standard session template. The long tail of Linear operations remains reachable on demand viaToolSearchwhen genuinely needed.The SDK only exposes
alwaysLoadper-server (not per-tool for remote HTTP servers), so curating the essentials into always-loaded local servers is the mechanism that satisfies both goals: lean turn-1 context and no startup tool-search stall for the tools Cyrus relies on.Why this is safe
mcp__cyrus-tools/mcp__cyrus-docsare already in the default allowed-tool lists — no permission changes./settings/toolscatalog needs no update.Testing
packages/edge-worker/test/McpConfigService.alwaysLoad.test.ts— assertscyrus-tools/cyrus-docsarealwaysLoad, the remotelinearserver is left deferred, and CLI mode (no Linear client) still always-loadscyrus-docs. All 3 pass.McpConfigServicetypechecks clean and lints clean.Changelog
Added an entry under
## [Unreleased] → ### Changeddescribing the faster session startup.