refactor(eve): extract the local trace reader into a shared harness module

[chadhietala]

Stacked on #1443 — base is trace-span-content, review that first.

Reading the local trace spool — listing trace directories, parsing OTLP/JSON segments, assembling spans into ordered traces — lived inside the eve traces CLI command. The /traces viewer up-stack needs the same reads without going through CLI printing, and the scenario tests were already importing a CLI module to get at them.

What changed

The reading half of commands/trace.ts moves to #harness/local-trace-reader.js: listLocalTraces, readLocalTrace, assembleLocalTrace, parseLocalTraceSegment, describeLocalTraceSpan, and the LocalTrace/LocalTraceSpan types. The command becomes a thin CLI over the reader and keeps its behavior; the scenario test imports the reader directly instead of the command.

Two small additions ride along for consumers up-stack: assembled traces expose sessionIds (every agent.session.id seen in the trace, for matching a chat session to its trace) and window (the session-window index from #1410). The reader keeps its defensive posture — malformed segments are skipped, segments over 8 MiB are ignored, span ids are validated — so a spool being written or swept mid-read never throws.

Verification

The eve traces integration tests pass unchanged (7 tests — behavior-preservation is the point), plus workspace typecheck at this layer. Full sweep at the stack top.

[vercel]

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

Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview	Jul 31, 2026 1:53pm
eve-docs-4759	Ready	Preview, v0	Jul 31, 2026 1:53pm

[github-actions]

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

Key takeaways

• No notable deltas vs trace-span-content (a137db8).

Delta vs trace-span-content (a137db8)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	7.47 MB	7.47 MB	-767 B ✅
Package	Unpacked publish size	27.85 MB	27.85 MB	+2.5 kB ⚠️
Package	Installed footprint	84.82 MB	84.82 MB	+2.5 kB ⚠️
Package	Published files	2899	2901	+2
Package	Installed files	6692	6694	+2
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	16.91 MB	16.91 MB	-40 B ✅
Runtime	Public routes	11	11	0

Changed function payloads vs trace-span-content (a137db8) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/__server.func	changed	8.45 MB	8.45 MB	-20 B ✅	none
functions/.well-known/workflow/v1/flow.func	changed	8.45 MB	8.45 MB	-20 B ✅	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	123.23 MB	123.24 MB	+2.5 kB ⚠️
Installed packages	128	128	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	42.22 MB	42.22 MB	+2.5 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: 2026-07-31T13:54:45.168Z
• Route aliases: 11 public, 1 internal (12 total aliases)
• Vercel routes in config: 14
• Severity legend: 🔴 dominant/large, 🟠 notable, 🟡 watch, ⚪ small

Package Drill-Down

Package Details

• Package: eve@0.29.2
• Package directory: packages/eve
• Tarball: 7.47 MB (eve-0.29.2.tgz)
• Unpacked payload: 27.85 MB across 2901 published files
• Installed footprint: 84.82 MB across 6694 installed files
• Installed root package: 26.50 MB
• Installed dependencies: 58.33 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: 26.50 MB (31.2%)
• @rolldown/binding-linux-x64-gnu: 19.28 MB (22.7%)
• @rolldown/binding-wasm32-wasi: 10.66 MB (12.6%)
• ai: 6.56 MB (7.7%)
• zod: 5.07 MB (6.0%)

Publish payload breakdown

Published file size
🔴 dist/src/compiled/shadcn-registry/index.js       [##################......] 9.68 MB 34.8%
🟠 dist/src/compiled/@photon-ai/chat-adapter-ime... [####....................] 2.42 MB 8.7%
🟠 dist/src/compiled/experimental-ai-sdk-code-mo... [###.....................] 1.51 MB 5.4%
🟡 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                            [########################] 13.24 MB 47.5%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 26.50 MB 31.2%
🔴 @rolldown/binding-linux-x64-gnu [#################.......] 19.28 MB 22.7%
🔴 @rolldown/binding-wasm32-wasi   [##########..............] 10.66 MB 12.6%
🔴 ai                              [######..................] 6.56 MB 7.7%
🔴 zod                             [#####...................] 5.07 MB 6.0%
🟠 undici                          [###.....................] 3.50 MB 4.1%
🔴 Other installed packages        [############............] 13.26 MB 15.6%

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: 123.24 MB across 8570 installed files
• Installed packages: 128 total (122 transitive-only)
• dependencies: 4 direct packages totaling 42.22 MB
• devDependencies: 2 direct packages totaling 5.04 MB
• Other transitive package files: 75.97 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 (22.7%)
• eve: 26.50 MB (21.5%)
• @rolldown/binding-linux-x64-gnu: 19.28 MB (15.6%)
• @rolldown/binding-wasm32-wasi: 10.66 MB (8.6%)
• zod: 9.02 MB (7.3%)

Installed footprint breakdown

Installed package size
🔴 @typescript/typescript-linux-x64 [########################] 27.95 MB 22.7%
🔴 eve                              [#######################.] 26.50 MB 21.5%
🔴 @rolldown/binding-linux-x64-gnu  [#################.......] 19.28 MB 15.6%
🔴 @rolldown/binding-wasm32-wasi    [#########...............] 10.66 MB 8.6%
🔴 zod                              [########................] 9.02 MB 7.3%
🔴 ai                               [######..................] 6.56 MB 5.3%
🔴 Other installed packages         [####################....] 23.27 MB 18.9%

dependencies (4)

Package	Range	Installed size	Share
@vercel/connect	0.4.3	141.0 kB	0.1%
ai	^7.0.38	6.56 MB	5.3%
eve	file:eve-0.29.2.tgz	26.50 MB	21.5%
zod	4.4.3	9.02 MB	7.3%

devDependencies (2)

Package	Range	Installed size	Share
@types/node	24.x	2.54 MB	2.1%
typescript	7.0.2	2.50 MB	2.0%

Function Drill-Down

Payload Size Graph

Unique function payload size and share of total
🔴 functions/.well-known/workflow/v1/flow.func     [########################] 8.45 MB 50.0%
🔴 functions/__server.func                         [########################] 8.45 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 8.45 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.45 MB
Function files	8.45 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.31 MB (27.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [#######################.] 2.31 MB 27.4%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.59 MB 18.9%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.6%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.1%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.37 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 • 10 public routes, 1 internal alias • 8.45 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]/stream /eve/v1/session/reset
Internal aliases	/__server
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.45 MB
Function files	8.45 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.31 MB (27.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [#######################.] 2.31 MB 27.4%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.59 MB 18.9%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.6%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.1%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.36 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: 2.01 s -> 2.18 s (+169.6 ms) vs trace-span-content (a137db8).
• Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `trace-span-content (a137db8)`

Phase	Baseline	Current	Delta
extension.check	6.9 ms	1.2 ms	-5.7 ms
project.resolve	2.5 ms	0.6 ms	-1.9 ms
workspace.create	1.4 ms	0.8 ms	-0.6 ms
host.prepare	181.3 ms	320.7 ms	+139.4 ms
vercel.service-prefix.resolve	2.5 ms	2.4 ms	-0.1 ms
nitro.create	199.8 ms	247.2 ms	+47.4 ms
sandbox.prewarm	300.8 ms	233.0 ms	-67.8 ms
nitro.cache.prepare	0.3 ms	0.3 ms	0.0 ms
nitro.prepare	0.8 ms	0.9 ms	+0.1 ms
nitro.public-assets	0.7 ms	0.8 ms	+0.1 ms
nitro.prerender	0.5 ms	0.4 ms	-0.1 ms
nitro.bundle	1.29 s	1.34 s	+58.3 ms
nitro.cache.write	0.3 ms	0.4 ms	+0.1 ms
vercel.workflow-function.materialize	22.6 ms	23.7 ms	+1.1 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	4.2 ms	3.5 ms	-0.7 ms
workspace.remove	2.2 ms	2.1 ms	-0.1 ms

[ctgowrie]

Approving since other tracing related things are here but harness seems like the wrong package for this