feat(eve): buffer action progress lifecycle

[benpankow]

Summary

Related to #1673. Stacked on #2310.

Adds the sole producer-side buffering boundary for progress lifecycle events. The observer accumulates deterministic events at a logical turn-step boundary, splits batches at the protocol limit, and submits each batch through the existing best-effort callback; reduction and Slack rendering remain collector-owned.

This PR does not add another durable queue, transport, or provider debounce.

Validation

Focused buffer coverage demonstrates bounded batches and remainder flushing. The final stack passed 7,065 unit tests, 22 focused Workflow integration tests, type checking, invariant checks, and documentation validation.

Checklist

• This change was requested or approved by a maintainer
• 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)

Diff size

Docs — 1 file · +5 / -0

Adds the release note for buffered lifecycle delivery.

Implementation — 2 files · +49 / -12

Introduces the single producer buffer and routes the observer through it without changing collector ownership.

Tests — 1 file · +28 / -0

Covers protocol-sized submission and explicit remainder flushing.

[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 11:29pm
eve-docs-4759	Ready	Preview, v0	Aug 21, 2026 11:29pm
eve-pkg	Ready	Preview, v0	Aug 21, 2026 11:29pm

[github-actions]

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

Key takeaways

• No notable deltas vs ben/slack-activity-progress (adee8ba).

Delta vs ben/slack-activity-progress (adee8ba)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	8.19 MB	8.19 MB	+2.2 kB ⚠️
Package	Unpacked publish size	30.84 MB	30.84 MB	+8.1 kB ⚠️
Package	Installed footprint	74.92 MB	74.93 MB	+8.1 kB ⚠️
Package	Published files	3434	3440	+6
Package	Installed files	7145	7151	+6
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	18.37 MB	18.40 MB	+37.5 kB ⚠️
Runtime	Public routes	16	16	0

Changed function payloads vs ben/slack-activity-progress (adee8ba) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/__server.func	changed	9.18 MB	9.20 MB	+18.7 kB ⚠️	none
functions/.well-known/workflow/v1/flow.func	changed	9.18 MB	9.20 MB	+18.7 kB ⚠️	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	113.33 MB	113.34 MB	+8.1 kB ⚠️
Installed packages	121	121	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	45.36 MB	45.36 MB	+8.1 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: 2026-08-21T16:34:43.742Z
• 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: 8.19 MB (eve-0.44.0.tgz)
• Unpacked payload: 30.84 MB across 3440 published files
• Installed footprint: 74.93 MB across 7151 installed files
• Installed root package: 29.49 MB
• Installed dependencies: 45.44 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: 29.49 MB (39.4%)
• @rolldown/binding-linux-x64-gnu: 19.91 MB (26.6%)
• ai: 6.71 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 31.6%
🟠 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 1.6%
🔴 Other published files                            [########################] 16.11 MB 52.2%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 29.49 MB 39.4%
🔴 @rolldown/binding-linux-x64-gnu [################........] 19.91 MB 26.6%
🔴 ai                              [#####...................] 6.71 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: 113.34 MB across 9027 installed files
• Installed packages: 121 total (115 transitive-only)
• dependencies: 4 direct packages totaling 45.36 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: 29.49 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: 6.71 MB (5.9%)

Installed footprint breakdown

Installed package size
🔴 eve                              [########################] 29.49 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                               [#####...................] 6.71 MB 5.9%
🟠 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	6.71 MB	5.9%
eve	file:eve-0.44.0.tgz	29.49 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     [########################] 9.20 MB 50.0%
🔴 functions/__server.func                         [########################] 9.20 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 9.20 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	9.20 MB
Function files	9.20 MB across 50 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.15 MB (23.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                     [##################......] 2.15 MB 23.4%
🟠 _chunks/runtime-artifacts.mjs [###############.........] 1.81 MB 19.6%
🟡 _libs/undici.mjs              [########................] 980.5 kB 10.7%
🟡 _chunks/sandbox.mjs           [#######.................] 781.9 kB 8.5%
🟡 _chunks/frames-Dl2Hcma4.mjs   [######..................] 678.7 kB 7.4%
🟠 Other bundled files           [########################] 2.80 MB 30.4%

🧾 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 • 9.20 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	9.20 MB
Function files	9.20 MB across 50 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.15 MB (23.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                     [##################......] 2.15 MB 23.4%
🟠 _chunks/runtime-artifacts.mjs [###############.........] 1.81 MB 19.6%
🟡 _libs/undici.mjs              [########................] 980.5 kB 10.7%
🟡 _chunks/sandbox.mjs           [#######.................] 781.9 kB 8.5%
🟡 _chunks/frames-Dl2Hcma4.mjs   [######..................] 678.7 kB 7.4%
🟠 Other bundled files           [########################] 2.80 MB 30.4%

🧾 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: 1.60 s -> 1.58 s (-24.5 ms) vs ben/slack-activity-progress (adee8ba).
• Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `ben/slack-activity-progress (adee8ba)`

Phase	Baseline	Current	Delta
extension.check	10.1 ms	9.2 ms	-0.9 ms
project.resolve	0.3 ms	0.3 ms	0.0 ms
workspace.create	0.6 ms	0.6 ms	0.0 ms
host.prepare	214.5 ms	206.1 ms	-8.4 ms
vercel.service-prefix.resolve	1.1 ms	1.1 ms	0.0 ms
nitro.create	153.8 ms	150.2 ms	-3.6 ms
sandbox.prewarm	292.8 ms	252.4 ms	-40.4 ms
nitro.cache.prepare	0.2 ms	0.2 ms	0.0 ms
nitro.prepare	0.5 ms	0.4 ms	-0.1 ms
nitro.public-assets	0.5 ms	0.5 ms	0.0 ms
nitro.prerender	0.3 ms	0.3 ms	0.0 ms
nitro.bundle	880.4 ms	907.0 ms	+26.6 ms
nitro.cache.write	0.2 ms	0.2 ms	0.0 ms
vercel.workflow-function.materialize	45.3 ms	47.7 ms	+2.4 ms
agent-summary.emit	0.3 ms	0.4 ms	+0.1 ms
nitro.close	0.1 ms	0.1 ms	0.0 ms
output.publish	2.0 ms	2.0 ms	0.0 ms
workspace.remove	1.1 ms	1.1 ms	0.0 ms