feat(eve): dynamic model selection

[AndrewBarba]

Summary

• Adds defineDynamic({ fallback, events }) support for scoped dynamic agent model selection.
• Persists session- and turn-scoped model selections through context, with step-scoped selections kept live and virtual.
• Wires compiler, manifest, runtime, harness, docs, tests, and changeset for dynamic models on root agents and local subagents.

Behavior

Model selection can now run at session.started, turn.started, or step.started. Precedence is step over turn over session over fallback. Session and turn scopes store serializable model references; step scope may use direct provider LanguageModel objects.

Validation

• pnpm --filter eve exec vitest run --config vitest.unit.config.ts src/internal/authored-definition/core.test.ts src/compiler/manifest.test.ts src/compiler/normalize-agent-config.test.ts src/runtime/agent/resolve-model.test.ts src/context/dynamic-model-lifecycle.test.ts src/harness/tool-loop.test.ts
• pnpm --filter eve typecheck
• pnpm --filter eve test:unit
• pnpm docs:check
• pnpm guard:invariants
• pnpm lint
• git diff --check

[vercel]

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

Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview, Comment, Open in v0	Jul 7, 2026 8:10pm

2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
eve-docs-1644	Skipped	Open in v0	Jul 7, 2026 8:10pm
eve-docs-4759	Skipped	Open in v0	Jul 7, 2026 8:10pm

[github-actions]

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

Key takeaways

• No notable deltas vs main (b9a617a).

Delta vs main (b9a617a)

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	3.54 MB	3.55 MB	+4.6 kB ⚠️
Package	Unpacked publish size	12.86 MB	12.88 MB	+21.5 kB ⚠️
Package	Installed footprint	51.95 MB	51.97 MB	+21.5 kB ⚠️
Package	Published files	2457	2459	+2
Package	Installed files	5684	5686	+2
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	9.27 MB	9.29 MB	+12.6 kB ⚠️
Runtime	Public routes	9	9	0

Changed function payloads vs main (b9a617a) (2)

Function	Status	Baseline	Current	Delta	Route changes
functions/.well-known/workflow/v1/flow.func	changed	5.79 MB	5.80 MB	+12.1 kB ⚠️	none
functions/__server.func	changed	3.48 MB	3.48 MB	+518 B ⚠️	none

eve init install

Metric	Baseline	Current	Delta
Installed footprint	91.74 MB	91.76 MB	+21.5 kB ⚠️
Installed packages	120	120	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	27.02 MB	27.04 MB	+21.5 kB ⚠️
devDependency package bytes	4.81 MB	4.81 MB	0 B ➖

Build Metadata

• Preset: vercel
• Nitro: nitro@3.0.260610-beta
• Output directory: apps/fixtures/weather-agent/.vercel/output
• Build metadata timestamp: 2026-07-07T20:11:19.539Z
• 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@0.21.1
• Package directory: packages/eve
• Tarball: 3.55 MB (eve-0.21.1.tgz)
• Unpacked payload: 12.88 MB across 2459 published files
• Installed footprint: 51.97 MB across 5686 installed files
• Installed root package: 11.61 MB
• Installed dependencies: 40.37 MB
• Runtime dependencies: 1
• Peer dependencies: 5 (4 optional)

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

Heavy installed dependencies

• @rolldown/binding-linux-x64-gnu: 19.18 MB (36.9%)
• eve: 11.61 MB (22.3%)
• ai: 6.34 MB (12.2%)
• zod: 5.04 MB (9.7%)
• nitro: 2.41 MB (4.6%)

Publish payload breakdown

Published file size
🟠 dist/src/compiled/experimental-ai-sdk-code-mo... [####....................] 1.51 MB 11.7%
🟡 dist/src/compiled/@workflow/core/runtime.js      [##......................] 794.4 kB 6.2%
🟡 dist/src/compiled/@vercel/sandbox/index.js       [##......................] 632.2 kB 4.9%
🟡 dist/src/compiled/@chat-adapter/slack/index.js   [#.......................] 433.8 kB 3.4%
🟡 dist/src/compiled/_chunks/workflow/attribute-... [#.......................] 371.6 kB 2.9%
🔴 Other published files                            [########################] 9.14 MB 71.0%

Installed footprint breakdown

Installed package size
🔴 @rolldown/binding-linux-x64-gnu [########################] 19.18 MB 36.9%
🔴 eve                             [###############.........] 11.61 MB 22.3%
🔴 ai                              [########................] 6.34 MB 12.2%
🔴 zod                             [######..................] 5.04 MB 9.7%
🟠 nitro                           [###.....................] 2.41 MB 4.6%
🟡 rolldown                        [#.......................] 771.7 kB 1.5%
🔴 Other installed packages        [########................] 6.64 MB 12.8%

Runtime dependencies (1)

Package	Range	Notes
nitro	3.0.260610-beta

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: 91.76 MB across 7438 installed files
• Installed packages: 120 total (114 transitive-only)
• dependencies: 4 direct packages totaling 27.04 MB
• devDependencies: 2 direct packages totaling 4.81 MB
• Other transitive package files: 59.91 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: 29.69 MB (32.4%)
• @rolldown/binding-linux-x64-gnu: 19.18 MB (20.9%)
• eve: 11.61 MB (12.6%)
• zod: 9.00 MB (9.8%)
• ai: 6.34 MB (6.9%)

Installed footprint breakdown

Installed package size
🔴 @typescript/typescript-linux-x64 [########################] 29.69 MB 32.4%
🔴 @rolldown/binding-linux-x64-gnu  [###############.........] 19.18 MB 20.9%
🔴 eve                              [#########...............] 11.61 MB 12.6%
🔴 zod                              [#######.................] 9.00 MB 9.8%
🔴 ai                               [#####...................] 6.34 MB 6.9%
🟠 @types/node                      [##......................] 2.54 MB 2.8%
🔴 Other installed packages         [###########.............] 13.41 MB 14.6%

dependencies (4)

Package	Range	Installed size	Share
@vercel/connect	0.2.2	98.6 kB	0.1%
ai	^7.0.0	6.34 MB	6.9%
eve	file:eve-0.21.1.tgz	11.61 MB	12.6%
zod	4.4.3	9.00 MB	9.8%

devDependencies (2)

Package	Range	Installed size	Share
@types/node	24.x	2.54 MB	2.8%
typescript	7.0.1-rc	2.27 MB	2.5%

Function Drill-Down

Payload Size Graph

Unique function payload size and share of total
🔴 functions/.well-known/workflow/v1/flow.func     [########################] 5.80 MB 62.5%
🟠 functions/__server.func                         [##############..........] 3.48 MB 37.5%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 5.80 MB

Metric	Value
Public routes	/.well-known/workflow/v1/flow
Runtime	nodejs24.x
Handler	index.mjs
Payload	5.80 MB
Function files	5.80 MB across 26 files
Traced dependencies	0 B
Signal	🟠 Bundled file __eve_nitro_handler__.mjs is 2.03 MB (35.0%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 __eve_nitro_handler__.mjs              [########################] 2.03 MB 35.0%
🟠 _chunks/runtime.mjs                    [############............] 983.9 kB 17.0%
🟡 _chunks/sandbox.mjs                    [#########...............] 766.3 kB 13.2%
🟡 _chunks/attribute-changes-zAifvEhb.mjs [######..................] 473.4 kB 8.2%
🟡 _libs/@ai-sdk/gateway+[...].mjs        [#####...................] 413.5 kB 7.1%
🟠 Other bundled files                    [#############...........] 1.14 MB 19.6%

🧾 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 • 3.48 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	3.48 MB
Function files	3.48 MB across 21 files
Traced dependencies	0 B
Signal	🟠 Bundled file _chunks/dev-runtime-artifacts.mjs is 917.1 kB (26.3%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 _chunks/dev-runtime-artifacts.mjs      [########################] 917.1 kB 26.3%
🟠 _chunks/runtime.mjs                    [#######################.] 891.6 kB 25.6%
🟠 _chunks/sandbox.mjs                    [####################....] 766.3 kB 22.0%
🟡 _chunks/attribute-changes-zAifvEhb.mjs [############............] 449.0 kB 12.9%
⚪ _libs/zod.mjs                          [###.....................] 114.2 kB 3.3%
🟡 Other bundled files                    [#########...............] 343.9 kB 9.9%

🧾 Vercel Config

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