feat(eve): let a provider say how much of an event it needs by chadhietala · Pull Request #1823 · vercel/eve

chadhietala · 2026-08-07T23:06:57Z

Tenth and last PR of the instrumentation-providers stack. Base is
instr/09-docs-and-composition (#1795). Everything here is behind
experimental.instrumentationProviders, which stays off.

Problem

Capture policy lived entirely inside the OpenTelemetry layer. recordInputs and
recordOutputs were resolved per destination, unioned into the pipeline
settings, and enforced by contentFilteringProcessor — a span processor. Two
consequences, both of which the design doc calls out:

A provider authored under agent/instrumentation/ that is not an OTel
destination — an audit log, a metrics counter, a hosted eval SDK with its own
transport — received the prompt, the response, and every tool argument and
result, with no lever to decline them. The span-processor lever is reachable
only from inside the OTel pipeline, so it could not serve those providers at
all.
eve built the content projection on every event whether or not anything
downstream would read it. An agent tracing to a metadata-only destination
still paid to serialize each prompt.

Solution

A provider declares capture. "metadata" — the default — is structure,
identity, usage, and timing. "content" adds what the conversation said.

The bus computes the union across registered providers once and exposes it as
hooks.capturesContent. The AI SDK bridge reads that flag and skips
constructing content at all when it is false, which is what makes the saving
real rather than a filter applied after the fact. When some provider did ask,
the ones that did not are handed a stripped copy of the event — built at most
once per event and shared between them, since the original belongs to whoever
asked and must not be edited underneath them.

The OpenTelemetry pipeline is itself one provider in that list, and now declares
its own capture from the destinations behind it. That is what keeps the two
layers consistent: a pipeline whose destinations all declined content asks for
"metadata" like anything else, and the per-destination span processor keeps
serving OTel-only concerns, which the design explicitly preserves.

Behavior changes

Content fields become optional on the events that carry them: input on
model.call.started and action.started, content on
model.call.completed, and the payloads inside action.completed's output.
InstrumentationActionOutput's discriminator survives declining. Only the
inner output/error is stripped, so a provider counting tool failures never
has to ask for content to learn that one failed. Same for
model.call.completed's finishReason and usage.
The shipped agent/instrumentation.ts layout is unaffected. Its only event is
step.started, which is the runtimeContext surface rather than a bus
subscriber, and the OTel provider derives its capture from the same
recordInputs/recordOutputs it already honored.

Validation

pnpm fmt, pnpm lint, pnpm typecheck, pnpm guard:invariants,
pnpm docs:check, pnpm test:unit (6126 passed), pnpm test:integration (617
passed).

New unit coverage: the projection is absent end-to-end when no provider asked;
a metadata provider sharing a bus with a content one sees structure but not
content; and the capturesContent union itself.

Capture policy lived entirely inside the OpenTelemetry layer: recordInputs and recordOutputs were resolved per destination and enforced by a span processor, so a provider authored under agent/instrumentation/ saw the prompt, the response, and every tool payload with no lever to decline them — and eve built that projection whether or not anyone downstream would read it. A provider now declares capture. "metadata", the default, is structure, identity, usage, and timing; "content" adds what the conversation said. The bus computes the union once, and the AI SDK bridge skips building content when the union is false, so a directory in which nobody asked never serializes a prompt. Providers that did not ask are handed a stripped copy — built at most once per event and shared, since the original belongs to whoever did ask. The OpenTelemetry pipeline is one provider among them and declares its own capture from the destinations behind it, which is what keeps the two layers consistent: a pipeline whose destinations all declined asks for metadata, and the per-destination span processor keeps serving OTel-only concerns. Structure survives declining. action.completed still carries whether the tool returned or threw, so a provider counting failures never has to ask for content. Signed-off-by: Chad Hietala <chadhietala@gmail.com>

vercel · 2026-08-07T23:07:03Z

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Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview	Aug 7, 2026 11:08pm
eve-docs-4759	Ready	Preview, v0	Aug 7, 2026 11:08pm

github-actions · 2026-08-07T23:11:21Z

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

Key takeaways

No notable deltas vs instr/09-docs-and-composition (249dca0).

Delta vs `instr/09-docs-and-composition (249dca0)`

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	7.71 MB	7.71 MB	+1.1 kB ⚠️
Package	Unpacked publish size	28.88 MB	28.88 MB	+4.1 kB ⚠️
Package	Installed footprint	72.31 MB	72.31 MB	+4.1 kB ⚠️
Package	Published files	3086	3086	0
Package	Installed files	6794	6794	0
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	17.07 MB	17.07 MB	+352 B ⚠️
Runtime	Public routes	13	13	0

Changed function payloads vs instr/09-docs-and-composition (249dca0) (2)

Function	Status	Baseline	Current	Delta	Route changes
`functions/__server.func`	changed	8.53 MB	8.53 MB	+176 B ⚠️	none
`functions/.well-known/workflow/v1/flow.func`	changed	8.53 MB	8.53 MB	+176 B ⚠️	none

`eve init` install

Metric	Baseline	Current	Delta
Installed footprint	110.72 MB	110.72 MB	+4.1 kB ⚠️
Installed packages	121	121	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	43.35 MB	43.36 MB	+4.1 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: 2026-08-07T23:10:31.023Z
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@0.31.2
Package directory: packages/eve
Tarball: 7.71 MB (eve-0.31.2.tgz)
Unpacked payload: 28.88 MB across 3086 published files
Installed footprint: 72.31 MB across 6794 installed files
Installed root package: 27.52 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: 27.52 MB (38.1%)
@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 (4.8%)

Publish payload breakdown

Published file size
🔴 dist/src/compiled/shadcn-registry/index.js       [################........] 9.68 MB 33.5%
🟠 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/workflow/undici-CUI... [#.......................] 508.8 kB 1.8%
🟡 dist/src/compiled/_chunks/node/undici-DWL_MYm... [#.......................] 502.4 kB 1.7%
🔴 Other published files                            [########################] 14.26 MB 49.4%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 27.52 MB 38.1%
🔴 @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 4.8%
🟠 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: 110.72 MB across 8670 installed files
Installed packages: 121 total (115 transitive-only)
dependencies: 4 direct packages totaling 43.36 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 (25.2%)
eve: 27.52 MB (24.9%)
@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 25.2%
🔴 eve                              [########################] 27.52 MB 24.9%
🔴 @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         [##############..........] 16.71 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-0.31.2.tgz`	27.52 MB	24.9%
`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     [########################] 8.53 MB 50.0%
🔴 functions/__server.func                         [########################] 8.53 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 8.53 MB

Metric	Value
Public routes	`/.well-known/workflow/v1/flow`
Runtime	`nodejs24.x`
Handler	`index.mjs`
Payload	8.53 MB
Function files	8.53 MB across 44 files
Traced dependencies	0 B
Signal	🟠 Bundled file `index.mjs` is 2.33 MB (27.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.33 MB 27.4%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.63 MB 19.1%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.5%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.0%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.38 MB 27.9%

🧾 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 • 8.53 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	8.53 MB
Function files	8.53 MB across 44 files
Traced dependencies	0 B
Signal	🟠 Bundled file `index.mjs` is 2.33 MB (27.4%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.33 MB 27.4%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.63 MB 19.1%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.5%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.0%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.38 MB 27.9%

🧾 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: 2.04 s -> 2.23 s (+189.4 ms) vs instr/09-docs-and-composition (249dca0).
Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `instr/09-docs-and-composition (249dca0)`

Phase	Baseline	Current	Delta
`extension.check`	10.6 ms	1.1 ms	-9.5 ms
`project.resolve`	1.3 ms	0.6 ms	-0.7 ms
`workspace.create`	1.3 ms	0.6 ms	-0.7 ms
`host.prepare`	241.3 ms	206.4 ms	-34.9 ms
`vercel.service-prefix.resolve`	1.9 ms	1.9 ms	0.0 ms
`nitro.create`	196.8 ms	229.1 ms	+32.3 ms
`sandbox.prewarm`	221.5 ms	450.3 ms	+228.8 ms
`nitro.cache.prepare`	0.3 ms	0.3 ms	0.0 ms
`nitro.prepare`	0.7 ms	0.7 ms	0.0 ms
`nitro.public-assets`	0.8 ms	0.8 ms	0.0 ms
`nitro.prerender`	0.5 ms	0.5 ms	0.0 ms
`nitro.bundle`	1.34 s	1.31 s	-25.8 ms
`nitro.cache.write`	0.3 ms	0.3 ms	0.0 ms
`vercel.workflow-function.materialize`	21.4 ms	21.3 ms	-0.1 ms
`agent-summary.emit`	0.6 ms	0.6 ms	0.0 ms
`nitro.close`	0.2 ms	0.2 ms	0.0 ms
`output.publish`	3.2 ms	3.4 ms	+0.2 ms
`workspace.remove`	2.0 ms	1.8 ms	-0.2 ms

vercel Bot deployed to Preview – eve-docs-4759 August 7, 2026 23:07 View deployment

vercel Bot deployed to Preview – eve-docs August 7, 2026 23:08 View deployment

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feat(eve): let a provider say how much of an event it needs - #1823

feat(eve): let a provider say how much of an event it needs#1823
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Problem

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Behavior changes

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

Delta vs instr/09-docs-and-composition (249dca0)

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 `instr/09-docs-and-composition (249dca0)`

`eve init` install

`eve init` install details

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