feat: migrate to Sentry span streaming and sample noise at request start - #60
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Closes #52. Drops the `traceLifecycle: "static"` bridge and the `beforeSendTransaction` filter it kept alive. With streamed spans nothing can be dropped after it starts, so every noise rule becomes a rate in a `tracesSampler`: 0 for untracked scanner routes, tracked sub-paths with no MCP method, and the two handshake notifications; `HEARTBEAT_SPAN_KEEP_RATE` for ping, server/discover, tools/list and initialize; 1 otherwise. MCP child segments inherit the parent's decision so root and child are kept together. The sampler only sees headers, not the body. Legacy clients that omit `Mcp-Method` get the header synthesized from a bounded read of a small JSON POST body before the request enters `withSentry`; the MCP transport ignores the header, so behaviour is unchanged. `beforeSendSpan` now edits the streamed span shape: strips request attributes and removes `user.*` from anonymous `/mcp` segments. Co-authored-by: Claude <claude@anthropic.com>
`beforeSendSpan` only kept `user.*` when `user.email` was a string, so a service token (username, no email) lost its attribution on spans while the error path still treated it as identified. Both paths now share `isIdentifiedUser`, and the span rule lives in `anonymizeSpanWithoutIdentity` next to its event twin so the two cannot drift again. Co-authored-by: Claude <claude@anthropic.com>
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Reviewed by Cursor Bugbot for commit 28c4150. Configure here.
| * `app.server.response` still counts 100% of requests. | ||
| */ | ||
| export function rootSampleRate(input: RootSpanSampleInput): number { | ||
| if (typeof input.parentSampled === "boolean") return Number(input.parentSampled); |
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Incoming traces skip sampling rules
Medium Severity
rootSampleRate returns immediately from parentSampled, so a sentry-trace header skips every local rate. An unsampled parent drops tools/call traces; a sampled one keeps scanner routes and handshake noise. Sentry sets parentSampled from incoming trace headers on the HTTP root, not only for in-process MCP children.
Additional Locations (1)
Reviewed by Cursor Bugbot for commit 28c4150. Configure here.
| !Number.isSafeInteger(contentLength) || | ||
| contentLength <= 0 || | ||
| contentLength > MAX_INSPECTED_MCP_BODY_BYTES | ||
| ) { |
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Header synthesis loses healthcheck kind
Medium Severity
withMcpMethodHeader always writes Mcp-Method for known methods, so inspectMcpRequest takes the header path and calls classifyMcpMethod. That never reads clientInfo.name, so healthcheck initialize is recorded as control on app.mcp.request.kind instead of heartbeat.
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Reviewed by Cursor Bugbot for commit 28c4150. Configure here.
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Closes #52. Supersedes #59, which GitHub closed when the branch of #58 (now merged) was deleted. Review history and the fixed Bugbot finding are on #59. Intended for release as 0.9.0 (minor): the span shape Sentry receives changes.
What changes
traceLifecycle: "static"bridge and thebeforeSendTransactionfilter it kept alive. That option is removed in a future SDK major, so this unblocks the v12 bump.tracesSampler(rootSampleRateinsrc/telemetry.ts). Streamed spans cannot be dropped once started, so every old drop rule is now a rate:/.env,/wp-admin/*,/): 0/mcp/actuator/heapdump): 0notifications/initialized,notifications/roots/list_changed: 0ping,server/discover,tools/list,initialize:HEARTBEAT_SPAN_KEEP_RATE(1%)parentSampled, so thehttp.serverroot andmcp.serverchild are kept or dropped together.Mcp-Methodfor legacy clients. The sampler sees headers only. For a POST to a tracked route with a JSON body up to 64 KB and noMcp-Methodheader,withMcpMethodHeaderreads a clone of the body and sets the header to the method name when it is on the known-method allow-list. The MCP transport ignores this header, so protocol behaviour is unchanged. Unknown method names never become a header value.beforeSendSpanon the streamed shape: strips request attributes and removesuser.*from/mcpsegments that carry no email, keeping the anonymous posture fromTELEMETRY.md.app.server.responsestill counts 100% of requests, so dashboards are unaffected.Why
initializeis sampled as a wholeThe old filter singled out the uptime monitor by
clientInfo.namein the body. The sampler cannot read the body, and a real session's signal is in its tool calls, which stay at 100%, so everyinitializenow takes the heartbeat rate.TELEMETRY.mddocuments this.Verification
pnpm build,pnpm typecheck,pnpm test: 227 passed.rootSampleRateunit cases; worker test asserting streamed envelope items (is_segment,sentry.op, notype: transaction), nouser.*on anonymous/mcpspans, and heartbeat sampling end to end (modern ping with header and legacy ping without header produce no span at a stubbedMath.randomof 0.5; a legacytools/callproduces a segment taggedtools/call).After deploy, check in Sentry
initialize/pingspans at roughly 1% of the metric counthttp.serverandmcp.serversegmentsuser.*attributes on/mcpspansCreated with Claude Code