feat(eve): record agent.turn spans with real durations in local traces

[chadhietala]

Summary

Local traces record agent.turn as a zero-duration marker (plus a separate agent.turn.terminal marker), because a live span object cannot survive a Workflow step boundary. So eve traces falls back to descendant extents and third-party OTel backends report 0ms for every turn.

A turn has a guaranteed close — its session transition — so the marker isn't required (noted as a follow-up in research/provider-neutral-local-observability.md). Now the turn's span id is allocated at turn.started and persisted with its start time; descendants parent through it as before, and the real agent.turn span is emitted when the turn settles, via a primed id generator shared with registerOTel, so it carries the pre-allocated id regardless of which worker settles. agent.turn.terminal is gone — its events land on the turn span.

• agent.session window roots remain markers: an idle session never closes.
• Sampling is unchanged: the turn context copies the window root's recorded flags.
• Production tracing (defineInstrumentation / ai.eve.turn) is untouched.
• Trade-off: a turn that never settles emits no turn span; its descendants render as roots in eve traces. Turn state from an older dev worker is dropped on deserialize (pre-1.0, no legacy fallback).

Validation

• pnpm build, fmt, lint, typecheck, guard:invariants, docs:check — pass
• Unit tier: 6024 passed (new: cross-worker settle keeps the allocated id; turn extent encloses its steps; codec round-trip)
• Integration tier: 602 passed; scenario local-instrumentation-runtime.scenario.test.ts: 2 passed — proves the real registerOTel + primed generator path end to end

Checklist

• I linked an issue with prior discussion confirming this change is wanted
• I ran the relevant checks from CONTRIBUTING.md
• I added tests and documentation where relevant
• I added a changeset if this touches the published eve package
• DCO sign-off passes for every commit (git commit --signoff)

No linked issue: this was flagged as "tracked separately" in the research doc rather than a GitHub issue.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
eve-docs	Building	Preview	Aug 7, 2026 2:52pm
eve-docs-4759	Ready	Preview, v0	Aug 7, 2026 2:52pm

[github-actions]

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

Key takeaways

• No notable deltas vs main (9d81515).

Delta vs main (9d81515)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	7.66 MB	7.66 MB	-575 B ✅
Package	Unpacked publish size	28.70 MB	28.71 MB	+5.9 kB ⚠️
Package	Installed footprint	72.13 MB	72.14 MB	+5.9 kB ⚠️
Package	Published files	3037	3043	+6
Package	Installed files	6745	6751	+6
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	16.99 MB	17.00 MB	+8.7 kB ⚠️
Runtime	Public routes	13	13	0

Changed function payloads vs main (9d81515) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/__server.func	changed	8.50 MB	8.50 MB	+4.3 kB ⚠️	none
functions/.well-known/workflow/v1/flow.func	changed	8.50 MB	8.50 MB	+4.3 kB ⚠️	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	110.54 MB	110.55 MB	+5.9 kB ⚠️
Installed packages	121	121	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	43.18 MB	43.19 MB	+5.9 kB ⚠️
devDependency package bytes	5.04 MB	5.04 MB	0 B ➖

eve init dependency changes vs main (9d81515)

dependencies

• Changed: eve@file:eve-0.31.0.tgz -> eve@file:eve-0.31.1.tgz

Build Metadata

• Preset: vercel
• Nitro: nitro@3.0.260610-beta
• Output directory: apps/fixtures/weather-agent/.vercel/output
• Build metadata timestamp: 2026-08-07T14:53:30.353Z
• 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@0.31.1
• Package directory: packages/eve
• Tarball: 7.66 MB (eve-0.31.1.tgz)
• Unpacked payload: 28.71 MB across 3043 published files
• Installed footprint: 72.14 MB across 6751 installed files
• Installed root package: 27.35 MB
• Installed dependencies: 44.78 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: 27.35 MB (37.9%)
• @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 33.7%
🟠 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/node/undici-DWL_MYm... [#.......................] 502.4 kB 1.8%
🟡 dist/src/compiled/_chunks/workflow/undici-DWL... [#.......................] 502.4 kB 1.8%
🔴 Other published files                            [########################] 14.09 MB 49.1%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 27.35 MB 37.9%
🔴 @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: 110.55 MB across 8627 installed files
• Installed packages: 121 total (115 transitive-only)
• dependencies: 4 direct packages totaling 43.19 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: 27.35 MB (24.7%)
• @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                              [#######################.] 27.35 MB 24.7%
🔴 @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         [##############..........] 16.70 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-0.31.1.tgz	27.35 MB	24.7%
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     [########################] 8.50 MB 50.0%
🔴 functions/__server.func                         [########################] 8.50 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 8.50 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.50 MB
Function files	8.50 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.32 MB (27.3%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [#######################.] 2.32 MB 27.3%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.62 MB 19.0%
🟡 _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 28.0%

🧾 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 • 8.50 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	8.50 MB
Function files	8.50 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.32 MB (27.3%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [#######################.] 2.32 MB 27.3%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.62 MB 19.0%
🟡 _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 28.0%

🧾 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: 2.15 s -> 2.03 s (-123.9 ms) vs main (9d81515).
• Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `main (9d81515)`

Phase	Baseline	Current	Delta
extension.check	1.1 ms	1.1 ms	0.0 ms
project.resolve	0.6 ms	0.7 ms	+0.1 ms
workspace.create	0.7 ms	0.7 ms	0.0 ms
host.prepare	224.4 ms	166.6 ms	-57.8 ms
vercel.service-prefix.resolve	2.4 ms	2.1 ms	-0.3 ms
nitro.create	246.0 ms	239.0 ms	-7.0 ms
sandbox.prewarm	237.5 ms	181.6 ms	-55.9 ms
nitro.cache.prepare	0.3 ms	0.3 ms	0.0 ms
nitro.prepare	0.9 ms	1.0 ms	+0.1 ms
nitro.public-assets	0.8 ms	0.8 ms	0.0 ms
nitro.prerender	0.6 ms	0.5 ms	-0.1 ms
nitro.bundle	1.40 s	1.40 s	-5.1 ms
nitro.cache.write	0.5 ms	0.5 ms	0.0 ms
vercel.workflow-function.materialize	23.4 ms	25.3 ms	+1.9 ms
agent-summary.emit	0.6 ms	0.6 ms	0.0 ms
nitro.close	0.1 ms	0.1 ms	0.0 ms
output.publish	3.5 ms	3.7 ms	+0.2 ms
workspace.remove	2.2 ms	2.3 ms	+0.1 ms