fix(eve): streaming - deduplicate replayed workflow events

[AndrewBarba]

Summary

• stamp durable stream events with stable IDs derived from the logical session turn, canonical event payload, and payload occurrence
• suppress repeated event IDs in ClientSession while advancing streamIndex across every physical record
• document the behavior, bump the stream protocol version, and add a patch changeset

Why

Workflow delivery is at least once. A repeated delivery can invoke a new physical Workflow step with stale session state after the first invocation has already written to the durable stream, causing TypeScript SDK consumers to observe the same logical turn more than once. Stable logical IDs let the client hide those replay records without corrupting its index-based reconnect cursor.

Workflow step IDs are stable across attempts of one invocation, but repeated delivery can create a second invocation with a different step ID. The event identity therefore uses eve's stable session ID and logical turn sequence instead.

Payload-derived IDs remain stable when independent parallel emissions change order. A per-payload occurrence counter preserves legitimately repeated identical events, while changed replay output receives a new ID instead of being silently discarded.

Impact

Iterators, reducers, and MessageResult.events no longer receive duplicate events during the lifetime of a ClientSession. Existing servers without meta.id remain compatible and their events pass through unchanged.

The seen-ID set is intentionally in-memory and is not serialized into SessionState; reconstructing a client between an original event and a later replay cannot deduplicate that record.

Validation

• pnpm lint
• pnpm --filter eve typecheck
• pnpm docs:check
• pnpm guard:invariants
• pnpm --filter eve test:unit — 4,192 passed, 1 skipped
• pnpm --filter eve exec vitest run --config vitest.integration.config.ts src/execution/workflow-entry.integration.test.ts — 8 passed

[vercel]

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Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview, Comment, Open in v0	Jun 26, 2026 8:57pm

[github-actions]

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

Key takeaways

• No notable deltas vs main (ddda14c).

Delta vs main (ddda14c)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	3.47 MB	3.47 MB	+2.2 kB ⚠️
Package	Unpacked publish size	12.60 MB	12.60 MB	+3.8 kB ⚠️
Package	Installed footprint	52.58 MB	52.59 MB	+3.8 kB ⚠️
Package	Published files	2359	2361	+2
Package	Installed files	5567	5569	+2
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	9.70 MB	9.70 MB	+1.3 kB ⚠️
Runtime	Public routes	9	9	0

Changed function payloads vs main (ddda14c) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/.well-known/workflow/v1/flow.func	changed	5.71 MB	5.71 MB	+1.5 kB ⚠️	none
functions/__server.func	changed	3.99 MB	3.99 MB	-144 B ✅	none

Build Metadata

• Preset: vercel
• Nitro: nitro@3.0.260610-beta
• Output directory: apps/fixtures/weather-agent/.vercel/output
• Build metadata timestamp: 2026-06-26T20:58:11.065Z
• Route aliases: 9 public, 1 internal (10 total aliases)
• Vercel routes in config: 10
• Severity legend: 🔴 dominant/large, 🟠 notable, 🟡 watch, ⚪ small

Package Drill-Down

Package Details

• Package: eve@0.15.5
• Package directory: packages/eve
• Tarball: 3.47 MB (eve-0.15.5.tgz)
• Unpacked payload: 12.60 MB across 2361 published files
• Installed footprint: 52.59 MB across 5569 installed files
• Installed root package: 11.33 MB
• Installed dependencies: 41.26 MB
• Runtime dependencies: 1
• Peer dependencies: 12 (11 optional)

Installed footprint is measured from an isolated temporary npm install of the packed tarball.

Heavy installed dependencies

• @rolldown/binding-linux-x64-gnu: 20.26 MB (38.5%)
• eve: 11.33 MB (21.5%)
• ai: 6.26 MB (11.9%)
• zod: 5.04 MB (9.6%)
• nitro: 2.41 MB (4.6%)

Publish payload breakdown

Published file size
🟠 dist/src/compiled/experimental-ai-sdk-code-mo... [####....................] 1.51 MB 12.0%
🟡 dist/src/compiled/@workflow/core/runtime.js      [##......................] 788.4 kB 6.3%
🟡 dist/src/compiled/@vercel/sandbox/index.js       [##......................] 632.0 kB 5.0%
🟡 dist/src/compiled/@chat-adapter/slack/index.js   [#.......................] 438.4 kB 3.5%
🟡 dist/src/compiled/_chunks/workflow/attribute-... [#.......................] 371.6 kB 2.9%
🔴 Other published files                            [########################] 8.86 MB 70.3%

Installed footprint breakdown

Installed package size
🔴 @rolldown/binding-linux-x64-gnu [########################] 20.26 MB 38.5%
🔴 eve                             [#############...........] 11.33 MB 21.5%
🔴 ai                              [#######.................] 6.26 MB 11.9%
🔴 zod                             [######..................] 5.04 MB 9.6%
🟠 nitro                           [###.....................] 2.41 MB 4.6%
🟡 rolldown                        [#.......................] 771.7 kB 1.5%
🔴 Other installed packages        [########................] 6.52 MB 12.4%

Runtime dependencies (1)

Package	Range	Notes
nitro	3.0.260610-beta

Peer dependencies (12)

Package	Range	Notes
@opentelemetry/api	^1.0.0	optional peer
@sveltejs/kit	^2.0.0	optional peer
ai	catalog:
braintrust	^3.0.0	optional peer
just-bash	^3.0.0	optional peer
microsandbox	^0.5.0	optional peer
next	^16.0.0	optional peer
nuxt	^4.0.0	optional peer
react	^19.0.0	optional peer
svelte	^5.0.0	optional peer
vite	^8.0.0	optional peer
vue	^3.5.0	optional peer

Function Drill-Down

Payload Size Graph

Unique function payload size and share of total
🔴 functions/.well-known/workflow/v1/flow.func     [########################] 5.71 MB 58.9%
🔴 functions/__server.func                         [#################.......] 3.99 MB 41.1%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 5.71 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	5.71 MB
Function files	5.71 MB across 26 files
Traced dependencies	0 B
Signal	🟠 Bundled file __eve_nitro_handler__.mjs is 1.95 MB (34.1%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 __eve_nitro_handler__.mjs              [########################] 1.95 MB 34.1%
🟠 _chunks/runtime.mjs                    [############............] 975.4 kB 17.1%
🟡 _chunks/sandbox.mjs                    [#########...............] 766.0 kB 13.4%
🟡 _chunks/attribute-changes-DUxG-Gic.mjs [######..................] 473.2 kB 8.3%
🟡 _libs/@ai-sdk/gateway+[...].mjs        [#####...................] 413.5 kB 7.2%
🟠 Other bundled files                    [##############..........] 1.14 MB 19.9%

🧾 Vercel Config

{
  "handler": "index.mjs",
  "launcherType": "Nodejs",
  "shouldAddHelpers": false,
  "supportsResponseStreaming": true,
  "runtime": "nodejs24.x",
  "environment": {
    "NODE_OPTIONS": "--experimental-require-module"
  },
  "maxDuration": "max",
  "experimentalTriggers": [
    {
      "type": "queue/v2beta",
      "topic": "__eve776561746865722d6167656e74_wkf_workflow_*",
      "consumer": "default",
      "retryAfterSeconds": 5,
      "initialDelaySeconds": 0
    }
  ]
}

---

🟠 functions/__server.func • 8 public routes, 1 internal alias • 3.99 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]/stream
Internal aliases	/__server
Runtime	nodejs24.x
Handler	index.mjs
Payload	3.99 MB
Function files	3.99 MB across 21 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 1.52 MB (38.0%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                              [########################] 1.52 MB 38.0%
🟠 _chunks/runtime.mjs                    [##############..........] 883.8 kB 22.2%
🟠 _chunks/sandbox.mjs                    [############............] 766.0 kB 19.2%
🟡 _chunks/attribute-changes-DUxG-Gic.mjs [#######.................] 448.9 kB 11.3%
⚪ _libs/zod.mjs                          [##......................] 114.2 kB 2.9%
🟡 Other bundled files                    [####....................] 258.8 kB 6.5%

🧾 Vercel Config

{
  "handler": "index.mjs",
  "launcherType": "Nodejs",
  "shouldAddHelpers": false,
  "supportsResponseStreaming": true,
  "runtime": "nodejs24.x"
}