feat(eve): emit vercel.session_id on agent spans when running on Vercel

[chadhietala]

What

Every agent span now carries vercel.session_id (set to the root session id) when running on Vercel. The attribute is omitted in local eve dev.

Why

Sessions window every 200 spans, so a single session spans multiple trace IDs. The root session id holds the full window chain together. Emitting it as vercel.session_id makes it easier for us to look up on Vercel.

The attribute is conditional (VERCEL_ENV is set and not eve dev) so local dev never carries platform-specific attributes.

Validation

• tsc --noEmit on the eve package (no new errors in tracing files)
• 41 unit tests in agent-otel-provider.test.ts pass, including 2 new tests verifying vercel.session_id is present when enabled and absent by default

[vercel]

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

Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview, v0	Aug 21, 2026 10:30pm
eve-docs-4759	Ready	Preview, v0	Aug 21, 2026 10:30pm
eve-pkg	Ready	Preview, v0	Aug 21, 2026 10:30pm

[github-actions]

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

Key takeaways

• No notable deltas vs main (a4fd288).

Delta vs main (a4fd288)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	8.18 MB	8.18 MB	-24 B ✅
Package	Unpacked publish size	30.81 MB	30.81 MB	+1.3 kB ⚠️
Package	Installed footprint	74.93 MB	74.93 MB	+1.3 kB ⚠️
Package	Published files	3404	3404	0
Package	Installed files	7117	7117	0
Package	Installed package instances	35	35	0
Package	Distinct installed package names	34	34	0
Package	Installed dependency edges	53	53	0
Package	Installed optional peer edges	47	47	0
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	18.20 MB	18.20 MB	-40 B ✅
Runtime	Public routes	16	16	0

Changed function payloads vs main (a4fd288) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/__server.func	changed	9.10 MB	9.10 MB	-20 B ✅	none
functions/.well-known/workflow/v1/flow.func	changed	9.10 MB	9.10 MB	-20 B ✅	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	113.34 MB	113.35 MB	+1.3 kB ⚠️
Installed packages	121	121	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	45.37 MB	45.37 MB	+1.3 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: 2026-08-21T22:31:42.507Z
• Route aliases: 16 public, 1 internal (17 total aliases)
• Vercel routes in config: 19
• Severity legend: 🔴 dominant/large, 🟠 notable, 🟡 watch, ⚪ small

Package Drill-Down

Package Details

• Package: eve@0.44.0
• Package directory: packages/eve
• Tarball: 8.18 MB (eve-0.44.0.tgz)
• Unpacked payload: 30.81 MB across 3404 published files
• Installed footprint: 74.93 MB across 7117 installed files
• Installed root package: 29.45 MB
• Installed dependencies: 45.48 MB
• Installed package instances: 35
• Distinct installed package names: 34
• Installed dependency edges: 53
• Installed optional peer edges: 47
• Runtime dependencies: 2
• Peer dependencies: 5 (4 optional)

Installed footprint is measured from an isolated temporary npm install of the packed tarball.
Graph metrics read only package.json files in package directories directly beneath a node_modules boundary, including nested boundaries. Each directory is one package instance; distinct names come from those manifests. Dependency edges count each unique name in dependencies or optionalDependencies per instance; optional peer edges count peerDependencies marked optional.

Heavy installed dependencies

• eve: 29.45 MB (39.3%)
• @rolldown/binding-linux-x64-gnu: 19.91 MB (26.6%)
• ai: 6.75 MB (9.0%)
• zod: 5.07 MB (6.8%)
• undici: 3.50 MB (4.7%)

Publish payload breakdown

Published file size
🔴 dist/src/compiled/shadcn-registry/index.js       [###############.........] 9.76 MB 31.7%
🟠 dist/src/compiled/@photon-ai/chat-adapter-ime... [####....................] 2.44 MB 7.9%
🟠 dist/src/compiled/experimental-ai-sdk-code-mo... [##......................] 1.51 MB 4.9%
🟡 dist/src/compiled/_chunks/workflow/undici-Dzn... [#.......................] 512.7 kB 1.7%
🟡 dist/src/compiled/_chunks/node/undici-CUIybhQ... [#.......................] 508.8 kB 1.7%
🔴 Other published files                            [########################] 16.08 MB 52.2%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 29.45 MB 39.3%
🔴 @rolldown/binding-linux-x64-gnu [################........] 19.91 MB 26.6%
🔴 ai                              [######..................] 6.75 MB 9.0%
🔴 zod                             [####....................] 5.07 MB 6.8%
🟠 undici                          [###.....................] 3.50 MB 4.7%
🟠 nitro                           [##......................] 2.41 MB 3.2%
🔴 Other installed packages        [######..................] 7.84 MB 10.5%

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: 113.35 MB across 8993 installed files
• Installed packages: 121 total (115 transitive-only)
• dependencies: 4 direct packages totaling 45.37 MB
• devDependencies: 2 direct packages totaling 5.04 MB
• Other transitive package files: 62.93 MB

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

Heavy installed dependencies

• eve: 29.45 MB (26.0%)
• @typescript/typescript-linux-x64: 27.95 MB (24.7%)
• @rolldown/binding-linux-x64-gnu: 19.91 MB (17.6%)
• zod: 9.02 MB (8.0%)
• ai: 6.75 MB (6.0%)

Installed footprint breakdown

Installed package size
🔴 eve                              [########################] 29.45 MB 26.0%
🔴 @typescript/typescript-linux-x64 [#######################.] 27.95 MB 24.7%
🔴 @rolldown/binding-linux-x64-gnu  [################........] 19.91 MB 17.6%
🔴 zod                              [#######.................] 9.02 MB 8.0%
🔴 ai                               [######..................] 6.75 MB 6.0%
🟠 undici                           [###.....................] 3.50 MB 3.1%
🔴 Other installed packages         [##############..........] 16.75 MB 14.8%

dependencies (4)

Package	Range	Installed size	Share
@vercel/connect	0.4.3	141.0 kB	0.1%
ai	^7.0.58	6.75 MB	6.0%
eve	file:eve-0.44.0.tgz	29.45 MB	26.0%
zod	4.4.3	9.02 MB	8.0%

devDependencies (2)

Package	Range	Installed size	Share
@types/node	24.x	2.54 MB	2.2%
typescript	7.0.2	2.50 MB	2.2%

Function Drill-Down

Payload Size Graph

Unique function payload size and share of total
🔴 functions/.well-known/workflow/v1/flow.func     [########################] 9.10 MB 50.0%
🔴 functions/__server.func                         [########################] 9.10 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 9.10 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	9.10 MB
Function files	9.10 MB across 50 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.06 MB (22.6%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                     [##################......] 2.06 MB 22.6%
🟠 _chunks/runtime-artifacts.mjs [###############.........] 1.80 MB 19.8%
🟡 _libs/undici.mjs              [########................] 980.5 kB 10.8%
🟡 _chunks/sandbox.mjs           [#######.................] 781.9 kB 8.6%
🟡 _chunks/frames-Dl2Hcma4.mjs   [######..................] 678.7 kB 7.5%
🟠 Other bundled files           [########################] 2.80 MB 30.8%

🧾 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 • 15 public routes, 1 internal alias • 9.10 MB

Metric	Value
Public routes	/ /eve/v1/callback/[token] /eve/v1/connections/[name]/callback/[attemptId]/[token] /eve/v1/connections/[name]/callback/[token] /eve/v1/health /eve/v1/info /eve/v1/session /eve/v1/session/[parentSessionId]/subagents/[callId]/[childSessionId]/stream /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 /eve/v1/task-input/[token]
Internal aliases	/__server
Runtime	nodejs24.x
Handler	index.mjs
Payload	9.10 MB
Function files	9.10 MB across 50 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.06 MB (22.6%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                     [##################......] 2.06 MB 22.6%
🟠 _chunks/runtime-artifacts.mjs [###############.........] 1.80 MB 19.8%
🟡 _libs/undici.mjs              [########................] 980.5 kB 10.8%
🟡 _chunks/sandbox.mjs           [#######.................] 781.9 kB 8.6%
🟡 _chunks/frames-Dl2Hcma4.mjs   [######..................] 678.7 kB 7.5%
🟠 Other bundled files           [########################] 2.80 MB 30.8%

🧾 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: 2.29 s -> 2.48 s (+180.8 ms) vs main (a4fd288).
• Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `main (a4fd288)`

Phase	Baseline	Current	Delta
extension.check	10.4 ms	9.8 ms	-0.6 ms
project.resolve	0.4 ms	0.3 ms	-0.1 ms
workspace.create	0.8 ms	0.7 ms	-0.1 ms
host.prepare	325.5 ms	537.4 ms	+211.9 ms
vercel.service-prefix.resolve	2.4 ms	2.5 ms	+0.1 ms
nitro.create	260.5 ms	251.1 ms	-9.4 ms
sandbox.prewarm	266.4 ms	220.5 ms	-45.9 ms
nitro.cache.prepare	0.2 ms	0.2 ms	0.0 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	0.5 ms	0.6 ms	+0.1 ms
nitro.bundle	1.39 s	1.42 s	+24.0 ms
nitro.cache.write	0.4 ms	0.4 ms	0.0 ms
vercel.workflow-function.materialize	25.3 ms	26.0 ms	+0.7 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	3.4 ms	3.5 ms	+0.1 ms
workspace.remove	2.2 ms	2.1 ms	-0.1 ms