feat(eve): run subagents as durable background tasks

[ruiconti]

Introduces the complete experimental.tasks runtime contract in one merge unit. The flag first appears together with the final model tools, persistence writer, stable agent identity, local/remote lifecycle routing, and release metadata.

Data flow

• before: a subagent call blocked its parent turn until the child settled
• after: dispatch returns one durable { taskId, agentId, status: \"working\" } receipt; task transitions later wake the parent through replay-identified session deliveries
• before: child HITL targeted a parent turn inbox
• after: the task run validates the outstanding batch, routes the complete request/challenge through the parent channel, delivers the answer to the exact local or remote child, then records answered

Correctness boundaries

Every accepted child turn rebinds local adapter or remote callback forwarding to its owning task. Duplicate action IDs are rejected before side effects. Task readiness is released only after the parent index commits, making a fast terminal child replay-recoverable. Cancellation waits for committed task state, aborts the executor, and reports one cancelled settlement with usage so the task hook can close.

One agent owns at most one nonterminal task. Failed and cancelled work retains usage without reviving terminal status. Terminal snapshots remain readable after task-run retention expires. Remote callbacks are schema-validated and task response capabilities must match the recorded child address.

Remote child streams use an authenticated parent-origin proxy. Clients receive a server-authored childStreamPath; parent credentials are never forwarded cross-origin and remote credentials never enter the event stream.

This replaces the semantic/protocol portions of the v3 stack (#1517-#1522 and #1756-#1758). PR 4 is the merge-gating E2E acceptance suite.

[vercel]

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

Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview	Aug 7, 2026 6:26pm
eve-docs-4759	Ready	Preview, v0	Aug 7, 2026 6:26pm

[github-actions]

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

Key takeaways

• Runtime delta: public routes 13 -> 15 (+2); 1 changed payload.

Delta vs tasks-v4/02-create-once (c5d02e5)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	7.67 MB	7.69 MB	+20.1 kB ⚠️
Package	Unpacked publish size	28.74 MB	28.82 MB	+79.6 kB ⚠️
Package	Installed footprint	72.17 MB	72.25 MB	+79.6 kB ⚠️
Package	Published files	3052	3078	+26
Package	Installed files	6760	6786	+26
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	17.15 MB	17.34 MB	+188.9 kB ⚠️
Runtime	Public routes	13	15	+2

Changed function payloads vs tasks-v4/02-create-once (c5d02e5) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/__server.func	changed	8.57 MB	8.67 MB	+94.4 kB ⚠️	public +/eve/v1/session/[parentSessionId]/subagents/[callId]/[childSessionId]/stream, +/eve/v1/task-input/[token]
functions/.well-known/workflow/v1/flow.func	changed	8.57 MB	8.67 MB	+94.4 kB ⚠️	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	110.58 MB	110.66 MB	+79.6 kB ⚠️
Installed packages	121	121	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	43.22 MB	43.30 MB	+79.6 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: 2026-08-07T05:50:31.969Z
• Route aliases: 15 public, 1 internal (16 total aliases)
• Vercel routes in config: 18
• Severity legend: 🔴 dominant/large, 🟠 notable, 🟡 watch, ⚪ small

Package Drill-Down

Package Details

• Package: eve@0.30.7
• Package directory: packages/eve
• Tarball: 7.69 MB (eve-0.30.7.tgz)
• Unpacked payload: 28.82 MB across 3078 published files
• Installed footprint: 72.25 MB across 6786 installed files
• Installed root package: 27.47 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: 27.47 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/node/undici-DWL_MYm... [#.......................] 502.4 kB 1.7%
🟡 dist/src/compiled/_chunks/workflow/undici-DWL... [#.......................] 502.4 kB 1.7%
🔴 Other published files                            [########################] 14.20 MB 49.3%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 27.47 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: 110.66 MB across 8662 installed files
• Installed packages: 121 total (115 transitive-only)
• dependencies: 4 direct packages totaling 43.30 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: 27.47 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                              [########################] 27.47 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         [##############..........] 16.70 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-0.30.7.tgz	27.47 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     [########################] 8.67 MB 50.0%
🔴 functions/__server.func                         [########################] 8.67 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 8.67 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.67 MB
Function files	8.67 MB across 44 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.47 MB (28.5%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.47 MB 28.5%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.63 MB 18.9%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.3%
🟡 _chunks/sandbox.mjs             [#######.................] 769.0 kB 8.9%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.0%
🟠 Other bundled files             [#######################.] 2.38 MB 27.5%

🧾 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 • 14 public routes, 1 internal alias • 8.67 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/[parentSessionId]/subagents/[callId]/[childSessionId]/stream /eve/v1/session/[sessionId] /eve/v1/session/[sessionId]/cancel /eve/v1/session/[sessionId]/stream /eve/v1/session/clear /eve/v1/session/compact /eve/v1/session/reset /eve/v1/task-input/[token]
Internal aliases	/__server
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.67 MB
Function files	8.67 MB across 44 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.47 MB (28.5%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.47 MB 28.5%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.63 MB 18.9%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.3%
🟡 _chunks/sandbox.mjs             [#######.................] 769.0 kB 8.9%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.0%
🟠 Other bundled files             [#######################.] 2.38 MB 27.5%

🧾 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: 1.75 s -> 1.96 s (+210.0 ms) vs tasks-v4/02-create-once (c5d02e5).
• Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `tasks-v4/02-create-once (c5d02e5)`

Phase	Baseline	Current	Delta
extension.check	5.9 ms	0.9 ms	-5.0 ms
project.resolve	1.3 ms	0.4 ms	-0.9 ms
workspace.create	0.8 ms	0.5 ms	-0.3 ms
host.prepare	192.3 ms	179.2 ms	-13.1 ms
vercel.service-prefix.resolve	1.3 ms	1.4 ms	+0.1 ms
nitro.create	174.2 ms	204.6 ms	+30.4 ms
sandbox.prewarm	290.5 ms	272.6 ms	-17.9 ms
nitro.cache.prepare	0.2 ms	0.2 ms	0.0 ms
nitro.prepare	0.6 ms	0.6 ms	0.0 ms
nitro.public-assets	0.6 ms	0.6 ms	0.0 ms
nitro.prerender	0.3 ms	0.4 ms	+0.1 ms
nitro.bundle	1.03 s	1.12 s	+88.6 ms
nitro.cache.write	0.3 ms	0.2 ms	-0.1 ms
vercel.workflow-function.materialize	48.1 ms	36.8 ms	-11.3 ms
agent-summary.emit	0.4 ms	0.5 ms	+0.1 ms
nitro.close	0.1 ms	0.2 ms	+0.1 ms
output.publish	7.5 ms	147.7 ms	+140.2 ms
workspace.remove	1.5 ms	1.6 ms	+0.1 ms

[ruiconti]

Recreated after stacked-base synchronization; replacement contains the correctness pass and same branch.

[ruiconti]

Replacement: #1806