feat(eve): support dynamic subagents

[ctgowrie]

Description

Closes #696.

Allow a declared subagent to export defineDynamic from its own agent.ts. Session- and turn-scoped resolvers return a defineAgent(...) configuration to expose the child, or null/undefined to omit it from direct and Workflow delegation. Resolver errors and invalid definitions also omit the child.

eve always compiles the subagent filesystem manifest. When selected, it injects the returned runtime agent configuration into that compiled child, so resolvers can choose different descriptions, models, model options, compaction settings, reasoning, output schemas, and limits without changing the child’s instructions, tools, skills, connections, sandbox, or nested subagents. Stale calls are rejected before dispatch.

This also documents the authoring contract, preserves selections across durable workflow steps and deployment revisions, and adds deterministic coverage for runtime model switching and nil omission.

How did you test your changes?

• pnpm typecheck
• pnpm lint
• pnpm guard:invariants
• pnpm docs:check
• pnpm test:unit
• pnpm test:integration
• focused compiler, lifecycle, model-selection, workflow-runtime, and runtime-graph unit tests after rebasing onto latest main
• EVE_E2E_MODEL=mock pnpm exec eve eval --strict dynamic-subagent from e2e/fixtures/agent-subagents

PR Checklist

• I linked an issue with prior discussion confirming this change is wanted
• 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)

[vercel]

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

Project	Deployment	Actions	Updated (UTC)
eve-docs	Building	Preview	Aug 1, 2026 3:15am
eve-docs-4759	Ready	Preview, v0	Aug 1, 2026 3:15am

[github-actions]

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

Key takeaways

• No notable deltas vs main (6ad578a).

Delta vs main (6ad578a)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	7.59 MB	7.59 MB	+5.8 kB ⚠️
Package	Unpacked publish size	28.44 MB	28.47 MB	+25.5 kB ⚠️
Package	Installed footprint	85.43 MB	85.45 MB	+25.5 kB ⚠️
Package	Published files	2952	2962	+10
Package	Installed files	6747	6757	+10
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	16.91 MB	16.94 MB	+27.6 kB ⚠️
Runtime	Public routes	11	11	0

Changed function payloads vs main (6ad578a) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/__server.func	changed	8.46 MB	8.47 MB	+13.8 kB ⚠️	none
functions/.well-known/workflow/v1/flow.func	changed	8.46 MB	8.47 MB	+13.8 kB ⚠️	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	123.84 MB	123.87 MB	+25.5 kB ⚠️
Installed packages	128	128	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	42.82 MB	42.85 MB	+25.5 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: 2026-08-01T03:16:54.392Z
• Route aliases: 11 public, 1 internal (12 total aliases)
• Vercel routes in config: 14
• Severity legend: 🔴 dominant/large, 🟠 notable, 🟡 watch, ⚪ small

Package Drill-Down

Package Details

• Package: eve@0.29.4
• Package directory: packages/eve
• Tarball: 7.59 MB (eve-0.29.4.tgz)
• Unpacked payload: 28.47 MB across 2962 published files
• Installed footprint: 85.45 MB across 6757 installed files
• Installed root package: 27.11 MB
• Installed dependencies: 58.34 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: 27.11 MB (31.7%)
• @rolldown/binding-linux-x64-gnu: 19.28 MB (22.6%)
• @rolldown/binding-wasm32-wasi: 10.66 MB (12.5%)
• ai: 6.57 MB (7.7%)
• zod: 5.07 MB (5.9%)

Publish payload breakdown

Published file size
🔴 dist/src/compiled/shadcn-registry/index.js       [#################.......] 9.68 MB 34.0%
🟠 dist/src/compiled/@photon-ai/chat-adapter-ime... [####....................] 2.42 MB 8.5%
🟠 dist/src/compiled/experimental-ai-sdk-code-mo... [###.....................] 1.51 MB 5.3%
🟡 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                            [########################] 13.85 MB 48.7%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 27.11 MB 31.7%
🔴 @rolldown/binding-linux-x64-gnu [#################.......] 19.28 MB 22.6%
🔴 @rolldown/binding-wasm32-wasi   [#########...............] 10.66 MB 12.5%
🔴 ai                              [######..................] 6.57 MB 7.7%
🔴 zod                             [####....................] 5.07 MB 5.9%
🟠 undici                          [###.....................] 3.50 MB 4.1%
🔴 Other installed packages        [############............] 13.26 MB 15.5%

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: 123.87 MB across 8633 installed files
• Installed packages: 128 total (122 transitive-only)
• dependencies: 4 direct packages totaling 42.85 MB
• devDependencies: 2 direct packages totaling 5.04 MB
• Other transitive package files: 75.98 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 (22.6%)
• eve: 27.11 MB (21.9%)
• @rolldown/binding-linux-x64-gnu: 19.28 MB (15.6%)
• @rolldown/binding-wasm32-wasi: 10.66 MB (8.6%)
• zod: 9.02 MB (7.3%)

Installed footprint breakdown

Installed package size
🔴 @typescript/typescript-linux-x64 [########################] 27.95 MB 22.6%
🔴 eve                              [#######################.] 27.11 MB 21.9%
🔴 @rolldown/binding-linux-x64-gnu  [#################.......] 19.28 MB 15.6%
🔴 @rolldown/binding-wasm32-wasi    [#########...............] 10.66 MB 8.6%
🔴 zod                              [########................] 9.02 MB 7.3%
🔴 ai                               [######..................] 6.57 MB 5.3%
🔴 Other installed packages         [####################....] 23.27 MB 18.8%

dependencies (4)

Package	Range	Installed size	Share
@vercel/connect	0.4.3	141.0 kB	0.1%
ai	^7.0.38	6.57 MB	5.3%
eve	file:eve-0.29.4.tgz	27.11 MB	21.9%
zod	4.4.3	9.02 MB	7.3%

devDependencies (2)

Package	Range	Installed size	Share
@types/node	24.x	2.54 MB	2.1%
typescript	7.0.2	2.50 MB	2.0%

Function Drill-Down

Payload Size Graph

Unique function payload size and share of total
🔴 functions/.well-known/workflow/v1/flow.func     [########################] 8.47 MB 50.0%
🔴 functions/__server.func                         [########################] 8.47 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 8.47 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.47 MB
Function files	8.47 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.33 MB (27.5%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.33 MB 27.5%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.60 MB 18.8%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.6%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.1%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.37 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 • 10 public routes, 1 internal alias • 8.47 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]/stream /eve/v1/session/reset
Internal aliases	/__server
Runtime	nodejs24.x
Handler	index.mjs
Payload	8.47 MB
Function files	8.47 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file index.mjs is 2.33 MB (27.5%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.33 MB 27.5%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.60 MB 18.8%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.6%
🟡 _chunks/sandbox.mjs             [########................] 769.0 kB 9.1%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.36 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: 2.15 s -> 2.08 s (-69.4 ms) vs main (6ad578a).
• Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `main (6ad578a)`

Phase	Baseline	Current	Delta
extension.check	6.7 ms	1.0 ms	-5.7 ms
project.resolve	2.5 ms	0.5 ms	-2.0 ms
workspace.create	1.1 ms	0.7 ms	-0.4 ms
host.prepare	302.4 ms	250.0 ms	-52.4 ms
vercel.service-prefix.resolve	1.8 ms	1.7 ms	-0.1 ms
nitro.create	187.3 ms	214.5 ms	+27.2 ms
sandbox.prewarm	398.1 ms	334.8 ms	-63.3 ms
nitro.cache.prepare	0.2 ms	0.3 ms	+0.1 ms
nitro.prepare	0.7 ms	0.7 ms	0.0 ms
nitro.public-assets	0.7 ms	0.7 ms	0.0 ms
nitro.prerender	0.4 ms	0.5 ms	+0.1 ms
nitro.bundle	1.22 s	1.25 s	+27.5 ms
nitro.cache.write	0.3 ms	0.3 ms	0.0 ms
vercel.workflow-function.materialize	20.1 ms	19.5 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	3.1 ms	3.2 ms	+0.1 ms
workspace.remove	1.7 ms	1.8 ms	+0.1 ms

[AndrewBarba]

Can we keep description required here? The parent model needs it to know when it should call the subagent. For dynamic subagents, could we require the description up front and only resolve availability and model settings at runtime?

[ctgowrie]

Yes. Improving types to make this more clearn

[AndrewBarba]

Could we use this same effective agent when building the execution step below? The model call uses the selected model, but session.started still reports the placeholder model from the compiled manifest.

[ctgowrie]

On it