feat(eve): build the OTel pipeline from a declared value

[chadhietala]

Fourth in the instrumentation-provider stack, on top of #1677.

Why

eve registered the tracer provider and the local trace spool as one unit inside installLocalInstrumentationRuntime. So the spool could not be one processor among several, and an authored backend could not join the pipeline at all — it could only take the global slot for itself.

Approach

Split it into the three pieces the pipeline actually has.

otel() declares, it does not register. A process holds one tracer provider and the second registerOTel is refused, so a provider that registered in its own setup would silently export nothing as soon as there were two. mergeOtelDeclarations concatenates spanProcessors in declaration order and refuses a second resource, sampler, or propagators, naming both declarations so the author can find them:

Instrumentation declares `sampler` in more than one `otel()` call (1 and 2).

Letting the first win would discard the rest silently, which is the failure the collection exists to prevent.

registerOtelPipeline proves the registration took. registerOTel returns void and reports a refusal only through diag, which goes nowhere unless OTEL_LOG_LEVEL is set. eve checks both halves itself: that a probe span is visible to the active context, and that a probe processor was actually handed it. The second half was previously AgentTraceSpanProcessor.isAttached(); it belongs to registration, not to the spool, so it moved and isAttached is gone.

localTraces() is self-contained. It owns session liveness, retention pruning, and its own onEnd accept filter — so none of that reaches an author's exporters, which was the one thing that would have broken had the filter been hoisted into otel().

The default path is the first consumer. installLocalInstrumentationRuntime now reads otel({ spanProcessors: [localTraces()] }) — the same primitive an authored instrumentation.ts will use, so it is exercised before anyone can author against it.

Also here

The vendored @vercel/otel declaration had been narrowed to what eve used: propagators was the literal ["none"], and attributes and traceSampler were absent entirely. Widened to the real surface, which is also what settles the public typing question — these come from the vendored copy, so authors need no peer dependency on @opentelemetry/sdk-trace-base.

Scope

Nothing is exported publicly yet. otel() and localTraces() are identical values under both authoring designs (providers: [otel(…)] versus a file's default export), so this deliberately does not decide providers array versus instrumentation/<provider>.ts.

Verification

• pnpm fmt, pnpm lint, pnpm guard:invariants
• pnpm --filter eve typecheck
• pnpm test:unit — 5,907 passed
• pnpm test:integration — 575 passed
• local-instrumentation-runtime.scenario.test.ts — 2 passed
• Falsified both silent-failure guards: forcing the probe check to false fails all three registration tests, and dropping the releaseSession return fails the liveness test.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview	Aug 8, 2026 2:12pm
eve-docs-4759	Ready	Preview, v0	Aug 8, 2026 2:12pm

[vercel]

Additional Suggestion:

Scenario test asserts the outdated conflict error message /another runtime already exists/u, which no longer matches the error thrown after conflict detection moved into registerOtelPipeline.

[github-actions]

Bundle + Package Summary: apps/fixtures/weather-agent

Key takeaways

• No notable deltas vs instr/03-action-kind (5e53377).

Delta vs instr/03-action-kind (5e53377)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	7.69 MB	7.69 MB	+2.3 kB ⚠️
Package	Unpacked publish size	28.80 MB	28.81 MB	+8.0 kB ⚠️
Package	Installed footprint	72.23 MB	72.24 MB	+8.0 kB ⚠️
Package	Published files	3063	3069	+6
Package	Installed files	6773	6779	+6
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	17.07 MB	17.07 MB	-40 B ✅
Runtime	Public routes	13	13	0

Changed function payloads vs instr/03-action-kind (5e53377) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/__server.func	changed	8.53 MB	8.53 MB	-20 B ✅	none
functions/.well-known/workflow/v1/flow.func	changed	8.53 MB	8.53 MB	-20 B ✅	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	110.65 MB	110.65 MB	+8.0 kB ⚠️
Installed packages	121	121	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	43.28 MB	43.29 MB	+8.0 kB ⚠️
devDependency package bytes	5.04 MB	5.04 MB	0 B ➖

Build Metadata

• Preset: vercel
• Nitro: nitro@3.0.260610-beta
• Output directory: apps/fixtures/weather-agent/.vercel/output
• Build metadata timestamp: 2026-08-08T14:13:45.186Z
• Route aliases: 13 public, 1 internal (14 total aliases)
• Vercel routes in config: 16
• Severity legend: 🔴 dominant/large, 🟠 notable, 🟡 watch, ⚪ small

Package Drill-Down

Package Details

• Package: eve@0.31.3
• Package directory: packages/eve
• Tarball: 7.69 MB (eve-0.31.3.tgz)
• Unpacked payload: 28.81 MB across 3069 published files
• Installed footprint: 72.24 MB across 6779 installed files
• Installed root package: 27.45 MB
• Installed dependencies: 44.79 MB
• Runtime dependencies: 2
• Peer dependencies: 5 (4 optional)

Installed footprint is measured from an isolated temporary npm install of the packed tarball.

Heavy installed dependencies

• eve: 27.45 MB (38.0%)
• @rolldown/binding-linux-x64-gnu: 19.35 MB (26.8%)
• ai: 6.67 MB (9.2%)
• zod: 5.07 MB (7.0%)
• undici: 3.50 MB (4.9%)

Publish payload breakdown

Published file size
🔴 dist/src/compiled/shadcn-registry/index.js       [################........] 9.68 MB 33.6%
🟠 dist/src/compiled/@photon-ai/chat-adapter-ime... [####....................] 2.42 MB 8.4%
🟠 dist/src/compiled/experimental-ai-sdk-code-mo... [###.....................] 1.51 MB 5.2%
🟡 dist/src/compiled/_chunks/workflow/undici-CUI... [#.......................] 508.8 kB 1.8%
🟡 dist/src/compiled/_chunks/node/undici-DWL_MYm... [#.......................] 502.4 kB 1.7%
🔴 Other published files                            [########################] 14.19 MB 49.2%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 27.45 MB 38.0%
🔴 @rolldown/binding-linux-x64-gnu [#################.......] 19.35 MB 26.8%
🔴 ai                              [######..................] 6.67 MB 9.2%
🔴 zod                             [####....................] 5.07 MB 7.0%
🟠 undici                          [###.....................] 3.50 MB 4.9%
🟠 nitro                           [##......................] 2.41 MB 3.3%
🔴 Other installed packages        [#######.................] 7.79 MB 10.8%

Runtime dependencies (2)

Package	Range	Notes
nitro	3.0.260610-beta
undici	8.9.0

Peer dependencies (5)

Package	Range	Notes
@opentelemetry/api	^1.0.0	optional peer
ai	catalog:
braintrust	^3.0.0	optional peer
just-bash	^3.0.0	optional peer
microsandbox	^0.5.0	optional peer

eve init install drill-down

eve init install details

• Command: eve init my-agent
• Package manager: npm
• Installed footprint: 110.65 MB across 8655 installed files
• Installed packages: 121 total (115 transitive-only)
• dependencies: 4 direct packages totaling 43.29 MB
• devDependencies: 2 direct packages totaling 5.04 MB
• Other transitive package files: 62.32 MB

Installed footprint is measured from an isolated temporary eve init my-agent using the current packed eve tarball.

Heavy installed dependencies

• @typescript/typescript-linux-x64: 27.95 MB (25.3%)
• eve: 27.45 MB (24.8%)
• @rolldown/binding-linux-x64-gnu: 19.35 MB (17.5%)
• zod: 9.02 MB (8.2%)
• ai: 6.67 MB (6.0%)

Installed footprint breakdown

Installed package size
🔴 @typescript/typescript-linux-x64 [########################] 27.95 MB 25.3%
🔴 eve                              [########################] 27.45 MB 24.8%
🔴 @rolldown/binding-linux-x64-gnu  [#################.......] 19.35 MB 17.5%
🔴 zod                              [########................] 9.02 MB 8.2%
🔴 ai                               [######..................] 6.67 MB 6.0%
🟠 undici                           [###.....................] 3.50 MB 3.2%
🔴 Other installed packages         [##############..........] 16.71 MB 15.1%

dependencies (4)

Package	Range	Installed size	Share
@vercel/connect	0.4.3	141.0 kB	0.1%
ai	^7.0.38	6.67 MB	6.0%
eve	file:eve-0.31.3.tgz	27.45 MB	24.8%
zod	4.4.3	9.02 MB	8.2%

devDependencies (2)

Package	Range	Installed size	Share
@types/node	24.x	2.54 MB	2.3%
typescript	7.0.2	2.50 MB	2.3%

Function Drill-Down

Payload Size Graph

Unique function payload size and share of total
🔴 functions/.well-known/workflow/v1/flow.func     [########################] 8.53 MB 50.0%
🔴 functions/__server.func                         [########################] 8.53 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 8.53 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.53 MB
Function files	8.53 MB across 44 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.34 MB (27.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.34 MB 27.4%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.63 MB 19.1%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.5%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.0%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.38 MB 27.9%

🧾 Vercel Config

{
  "handler": "index.mjs",
  "launcherType": "Nodejs",
  "shouldAddHelpers": false,
  "supportsResponseStreaming": true,
  "runtime": "nodejs24.x",
  "maxDuration": "max",
  "experimentalTriggers": [
    {
      "type": "queue/v2beta",
      "topic": "__eve776561746865722d6167656e74_wkf_workflow_*",
      "consumer": "default",
      "retryAfterSeconds": 5,
      "initialDelaySeconds": 0
    }
  ],
  "environment": {
    "WORKFLOW_PRECONDITION_GUARD": "1"
  }
}

---

🟠 functions/__server.func • 12 public routes, 1 internal alias • 8.53 MB

Metric	Value
Public routes	/ /eve/v1/callback/[token] /eve/v1/connections/[name]/callback/[token] /eve/v1/health /eve/v1/info /eve/v1/session /eve/v1/session/[sessionId] /eve/v1/session/[sessionId]/cancel /eve/v1/session/[sessionId]/clear /eve/v1/session/[sessionId]/compact /eve/v1/session/[sessionId]/reset /eve/v1/session/[sessionId]/stream
Internal aliases	/__server
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.53 MB
Function files	8.53 MB across 44 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.34 MB (27.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.34 MB 27.4%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.63 MB 19.1%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.5%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.0%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.38 MB 27.9%

🧾 Vercel Config

{
  "handler": "index.mjs",
  "launcherType": "Nodejs",
  "shouldAddHelpers": false,
  "supportsResponseStreaming": true,
  "runtime": "nodejs24.x"
}

Build Timing: e2e/fixtures/agent-tools-sandbox

This is an informational timing measurement inside eve build, from preflight through publication. Output-size measurement and profile writing are excluded.

Build mode: deployable Vercel build with sandbox template prewarm included.

• Build pipeline: 2.63 s -> 2.10 s (-535.5 ms) vs instr/03-action-kind (5e53377).
• Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `instr/03-action-kind (5e53377)`

Phase	Baseline	Current	Delta
extension.check	1.2 ms	1.2 ms	0.0 ms
project.resolve	0.5 ms	0.6 ms	+0.1 ms
workspace.create	0.6 ms	0.6 ms	0.0 ms
host.prepare	209.7 ms	199.0 ms	-10.7 ms
vercel.service-prefix.resolve	1.8 ms	1.7 ms	-0.1 ms
nitro.create	215.7 ms	218.1 ms	+2.4 ms
sandbox.prewarm	290.7 ms	298.8 ms	+8.1 ms
nitro.cache.prepare	0.3 ms	0.2 ms	-0.1 ms
nitro.prepare	0.7 ms	0.7 ms	0.0 ms
nitro.public-assets	0.7 ms	0.8 ms	+0.1 ms
nitro.prerender	0.4 ms	0.5 ms	+0.1 ms
nitro.bundle	1.87 s	1.32 s	-550.2 ms
nitro.cache.write	0.4 ms	0.3 ms	-0.1 ms
vercel.workflow-function.materialize	17.4 ms	48.0 ms	+30.6 ms
agent-summary.emit	0.5 ms	0.5 ms	0.0 ms
nitro.close	0.1 ms	0.1 ms	0.0 ms
output.publish	21.3 ms	5.5 ms	-15.8 ms
workspace.remove	1.7 ms	1.8 ms	+0.1 ms