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Guide for adding new AI SDK harness packages.
Passed 22 of 22 test cases with the skill, and 6 of 22 without it.
and 23 more in the full report
16 fixed6 passed either way0 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 16 test cases the skill fixed. Same model, same prompt, with and without the skill.
We are scaffolding `package.json` for a new `@ai-sdk/harness-agent` package by copying metadata from existing harness adapters. Which license and minimum Node version constraint should be defined?
| Checked | Without skill | With skill |
|---|---|---|
| Sets license to Apache-2.0. | Missed | Passed |
| Constrains engines node to >=22. | Missed | Passed |
The instructions your model reads when the skill loads.
This guide covers creating a new @ai-sdk/harness-<name> package for an agent harness.
Before evaluating a runtime, read Harness Requirements for feasibility criteria and capability gaps to document. Follow the requirements while implementing the harness package.
A harness can be host-driven, where the runtime runs in the host process and uses the sandbox remotely, or bridge-backed, where a small bridge runs inside the sandbox because the runtime needs local access to the sandbox filesystem or process environment. Prefer host-driven when the runtime supports it.
@ai-sdk/harness-<name> packages: Create an issue first to discuss whether the runtime belongs in this repo.See https://github.com/vercel/ai/pull/16255/changes for a complete example of adding a new harness.
The AI SDK uses a layered harness architecture following the adapter pattern:
@ai-sdk/harness): Defines interfaces like HarnessV1 and HarnessV1Session@ai-sdk/harness/utils): Shared code for implementing harnesses@ai-sdk/harness-<name>): Concrete adapters for harnesses@ai-sdk/harness/agent): The high-level user-facing HarnessAgent APICreate packages/harness-<name> with this baseline structure:
packages/harness-<name>/
├── src/
│ ├── index.ts
│ ├── <name>-harness.ts
│ ├── <name>-harness.test.ts
│ └── <name>-auth.ts # if the runtime needs auth resolution
test cases passed, vs 6 / 22 without
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