fix(eve): recover stalled client stream reads by vercel-gh-bot-5[bot] · Pull Request #1769 · vercel/eve

vercel-gh-bot-5 · 2026-08-07T04:39:38Z

Client event streams now recover when an HTTP response stays open but stops delivering bytes.

Why

A focused real-socket repro on 9d81515c7da96d43dbaf8d7b9429092d97b3ef27 received step.started, then left the first response open and silent. After 500 ms, the client had not reconnected from cursor 1, so session.completed remained unreachable.

The current retry path handles closed and failed responses. A silent reader.read() produces neither, which can leave a live session blocked indefinitely.

Approach

Race each NDJSON byte read against a 30-second idle deadline. When the deadline expires, cancel the stale response and reopen from the durable cursor.

Byte-idle reconnects do not consume the empty-stream retry budget. A healthy long-running step may produce no bytes for several minutes, so the client must keep following until an event or an explicit boundary arrives. { reconnect: false } and tail-relative streams keep their existing single-connection behavior.

HTTP response -> NDJSON byte read -> idle deadline
                                   -> cancel stale reader
                                   -> reopen from durable cursor

This builds on the diagnosis and transport cases from #1186 and the earlier proposal in #1710.

Verification

Main repro failed: the open response stayed blocked after 500 ms with no cursor reconnect
Candidate regression passed: step.started, cursor reconnect from 1, then session.completed
NDJSON unit test: 1 passed
Real-socket stream integration suite: 8 passed
pnpm --filter eve typecheck
pnpm --filter eve build:js
focused oxlint and oxfmt --check
both strict review passes approved the final diff

Requested by: ruiconti

Co-authored-by: ruiconti <1834568+ruiconti@users.noreply.github.com>

vercel · 2026-08-07T04:39:46Z

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Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview	Aug 7, 2026 4:41am
eve-docs-4759	Ready	Preview, v0	Aug 7, 2026 4:41am

github-actions · 2026-08-07T04:43:12Z

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	-518 B ✅
Package	Unpacked publish size	28.70 MB	28.71 MB	+3.1 kB ⚠️
Package	Installed footprint	72.13 MB	72.13 MB	+3.1 kB ⚠️
Package	Published files	3037	3037	0
Package	Installed files	6745	6745	0
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	16.99 MB	16.99 MB	-40 B ✅
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	8.49 MB	-20 B ✅	none
`functions/.well-known/workflow/v1/flow.func`	changed	8.50 MB	8.50 MB	-20 B ✅	none

`eve init` install

Metric	Baseline	Current	Delta
Installed footprint	110.54 MB	110.54 MB	+3.1 kB ⚠️
Installed packages	121	121	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	43.18 MB	43.18 MB	+3.1 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: 2026-08-07T04:42:19.408Z
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@0.31.0
Package directory: packages/eve
Tarball: 7.66 MB (eve-0.31.0.tgz)
Unpacked payload: 28.71 MB across 3037 published files
Installed footprint: 72.13 MB across 6745 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: 110.54 MB across 8621 installed files
Installed packages: 121 total (115 transitive-only)
dependencies: 4 direct packages totaling 43.18 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-0.31.0.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                         [########################] 8.49 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 2.31 MB (27.2%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [#######################.] 2.31 MB 27.2%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.62 MB 19.0%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.5%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.1%
🟡 _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 • 8.49 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	8.49 MB
Function files	8.49 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file `index.mjs` is 2.31 MB (27.2%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [#######################.] 2.31 MB 27.2%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.62 MB 19.1%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.5%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.1%
🟡 _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: 2.09 s -> 2.40 s (+308.5 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`	6.7 ms	1.1 ms	-5.6 ms
`project.resolve`	5.5 ms	0.6 ms	-4.9 ms
`workspace.create`	4.4 ms	0.7 ms	-3.7 ms
`host.prepare`	184.1 ms	159.9 ms	-24.2 ms
`vercel.service-prefix.resolve`	2.7 ms	2.7 ms	0.0 ms
`nitro.create`	218.5 ms	236.3 ms	+17.8 ms
`sandbox.prewarm`	254.0 ms	645.9 ms	+391.9 ms
`nitro.cache.prepare`	0.3 ms	0.3 ms	0.0 ms
`nitro.prepare`	0.8 ms	0.8 ms	0.0 ms
`nitro.public-assets`	0.8 ms	0.7 ms	-0.1 ms
`nitro.prerender`	0.6 ms	0.6 ms	0.0 ms
`nitro.bundle`	1.38 s	1.32 s	-61.8 ms
`nitro.cache.write`	0.4 ms	0.4 ms	0.0 ms
`vercel.workflow-function.materialize`	23.7 ms	23.1 ms	-0.6 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`	3.5 ms	3.5 ms	0.0 ms
`workspace.remove`	2.3 ms	2.0 ms	-0.3 ms

fix(eve): recover stalled client stream reads

12f2d83

Co-authored-by: ruiconti <1834568+ruiconti@users.noreply.github.com>

vercel Bot deployed to Preview – eve-docs-4759 August 7, 2026 04:40 View deployment

vercel Bot deployed to Preview – eve-docs August 7, 2026 04:41 View deployment

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fix(eve): recover stalled client stream reads - #1769

fix(eve): recover stalled client stream reads#1769
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Bundle + Package Summary: apps/fixtures/weather-agent

Delta vs main (9d81515)

eve init install

Package Details

eve init install details

Payload Size Graph

Top Function Payloads

Build Timing: e2e/fixtures/agent-tools-sandbox

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

Delta vs `main (9d81515)`

`eve init` install

`eve init` install details

Build Timing: `e2e/fixtures/agent-tools-sandbox`