---
title: "Skills Framework"
version: 3.8.6
lastUpdated: 2026-05-28
---

# Skills Framework

> **Source of truth:** `src/lib/skills/` and `src/app/api/skills/`
> **Last updated:** 2026-05-28 — v3.8.6

OmniRoute exposes an extensible Skills framework that lets language models (and operators) compose reusable capabilities — from filesystem reads and HTTP requests to sandboxed code execution and curated marketplace skills.

A skill is a versioned, schema-defined unit of work. OmniRoute can inject skills as tool definitions into outbound requests, intercept tool calls coming back from the model, run the matching handler, and feed the result back to the model so the conversation can continue. The model never sees the implementation — only the tool interface.

---

## Agent Skills vs Omni Skills

OmniRoute has two distinct but complementary skill systems:

| Dimension | **Omni Skills** (this doc) | **Agent Skills** |
| :--- | :--- | :--- |
| Purpose | LLM tool injection + sandboxed execution | SKILL.md catalog for external agents to discover and consume |
| Source of truth | `src/lib/skills/` + marketplace | `src/lib/agentSkills/` + `skills/` directory |
| Runtime mode | Injected into outbound requests, executed on tool-call events | Static markdown catalog + REST/MCP/A2A discovery endpoints |
| Who uses it | OmniRoute itself (combo routing, inbound LLM calls) | External agents, MCP clients, A2A orchestrators |
| Count | Variable (marketplace-driven) | 42 canonical entries (22 API + 20 CLI) |
| Format | `SkillDefinition` with tool schema + handler | `SKILL.md` frontmatter + markdown body |
| Discovery | `/api/skills/*` REST + `omniroute_skills_*` MCP tools | `/api/agent-skills/*` REST + `omniroute_agent_skills_*` MCP tools + A2A `list-capabilities` |

**Omni Skills** are the execution engine — they define what OmniRoute *can do* when an LLM invokes a tool.

**Agent Skills** are the documentation catalog — they explain to external agents *how to use* OmniRoute's REST API and CLI, with structured SKILL.md files that can be fed directly into agent prompts.

For the Agent Skills catalog, generator, MCP tools, and A2A skill, see [docs/frameworks/AGENT-SKILLS.md](./AGENT-SKILLS.md).

---

## Concepts

### Skill Sources

Three sources of skills coexist in the same registry:

1. **Built-in skills** (`src/lib/skills/builtins.ts`) — shipped with OmniRoute. Cover the common cases:
   - `file_read`, `file_write` — per-API-key sandbox workspace under `<DATA_DIR>/skills/workspaces/<hashed-key>/`
   - `http_request` — outbound HTTP through `safeOutboundFetch` with `guard: "public-only"`
   - `web_search` — pluggable search provider with caching (`executeWebSearch`)
   - `eval_code` — Docker-sandboxed `node` or `python` execution
   - `execute_command` — Docker-sandboxed shell command
   - `browser` — Playwright-backed scaffolding, disabled by default (`builtin/browser.ts`)
2. **SkillsMP** (the OmniRoute Marketplace) — fetched from `https://skillsmp.com/api/v1/skills/search`. Requires `skillsmpApiKey` in Settings.
3. **SkillsSH** (`skills.sh` community catalog) — fetched from `https://skills.sh/api/search`. No auth needed; SKILL.md content pulled from GitHub raw.

A single "active provider" controls which catalog the dashboard installs from (`src/lib/skills/providerSettings.ts`). Switch it under **Settings → Memory & Skills**. Default: `skillsmp`.

### Skill Identity

Skills are keyed by `name@version` in the in-memory registry (`src/lib/skills/registry.ts`). Version must be semver (`^\d+\.\d+\.\d+$`). `resolveVersion()` understands `^`, `~`, `>`, `>=`, `<`, `<=`, `==`, and exact-match constraints.

### Skill Mode

Each skill has a runtime mode that controls when it is injected:

| Mode   | Behavior                                                                                   |
| ------ | ------------------------------------------------------------------------------------------ |
| `on`   | Always injected as a tool definition                                                       |
| `off`  | Never injected, never executable                                                           |
| `auto` | Scored against the incoming request; injected only if score ≥ `AUTO_MIN_SCORE` (default 3) |

`auto` is the default for marketplace-installed skills. `enabled=true` and `mode="off"` together mean "registered but inactive" — toggling `enabled` via the legacy column also bumps `mode` so older codepaths stay consistent (`src/app/api/skills/[id]/route.ts`).

### Status (executions)

Skill executions are tracked in the `skill_executions` table with the following statuses (`src/lib/skills/types.ts`):

```ts
enum SkillStatus {
  PENDING = "pending",
  RUNNING = "running",
  SUCCESS = "success",
  ERROR = "error",
  TIMEOUT = "timeout",
}
```

### Registry Cache

`SkillRegistry` is a singleton with a 60-second TTL cache (`registry.ts:14`). `loadFromDatabase()` is idempotent and dedupes concurrent calls via `pendingLoad`. Any write (`register`/`unregister`/`unregisterById`) invalidates the cache. Look up versions via `getSkillVersions(name)` and `resolveVersion(name, constraint)`.

### Provider-Aware Injection

`injectSkills()` in `src/lib/skills/injection.ts` is the entry point that turns registered skills into provider-specific tool definitions:

- **OpenAI** — `{ type: "function", function: { name, description, parameters } }`
- **Anthropic** — `{ name, description, input_schema }`
- **Google (Gemini)** — `{ name, description, parameters }`

The tool name is encoded as `name@version` so the handler can pick the right version when the model calls it back.

### AUTO Scoring

When `mode="auto"`, each candidate skill is scored against the request context (`scoreAutoSkill()` in `injection.ts`):

| Signal                                         | Points       |
| ---------------------------------------------- | ------------ |
| Skill name appears verbatim in context         | +6           |
| Each name token matches a context token        | +2           |
| Each tag substring matches context             | +3           |
| Each description token matches context         | +1           |
| Background reason matches a name token         | +2 per token |
| Background reason matches a tag                | +2 per token |
| Provider hint in tags matches request provider | +2 / −2      |

Top `AUTO_MAX_SKILLS = 5` skills with `score >= AUTO_MIN_SCORE = 3` are injected. Ties are broken by `installCount` (desc), then alphabetical name (`injection.ts:225-235`).

### Tool Call Interception

`handleToolCallExecution()` in `src/lib/skills/interception.ts` is invoked by the chat handler after the upstream returns a tool-calling response:

1. `extractToolCalls()` reads provider-specific shapes (OpenAI `tool_calls` / Responses `function_call`, Anthropic `tool_use`, Gemini `functionCalls`).
2. Built-in tool aliases (e.g. `omniroute_web_search` → `web_search`) are resolved first. Built-in handlers run inline.
3. Anything else routes through `skillExecutor.execute(name@version, args, { apiKeyId, sessionId })`.
4. Results are spliced back into the response — `tool_results`, `function_call_output` items, or Anthropic `tool_result` blocks as appropriate.

`customSkillExecutionEnabled` in the execution context can be set to `false` to allow only built-in interception (used by request paths that explicitly disable user-defined handlers).

---

## Docker Sandbox

Non-builtin code paths (`eval_code`, `execute_command`) run inside Docker via `SandboxRunner` (`src/lib/skills/sandbox.ts`). Every container is launched with:

```
--rm --network none|bridge --cap-drop ALL
--security-opt no-new-privileges --pids-limit 100
--cpus <cpuLimit/1000> --memory <memoryLimit>m
--tmpfs /tmp:rw,noexec,nosuid,size=64m
--tmpfs /workspace:rw,noexec,nosuid,size=64m
--read-only (when readOnly=true)
```

Defaults (`SandboxRunner.DEFAULT_CONFIG`):

| Field            | Default         | Notes                                                |
| ---------------- | --------------- | ---------------------------------------------------- |
| `cpuLimit`       | 100 (= 0.1 CPU) | Divided by 1000 before passing to `--cpus`           |
| `memoryLimit`    | 256 MB          | Hard limit                                           |
| `timeout`        | 30000 ms        | Soft kill via `SIGTERM` + `docker kill`              |
| `networkEnabled` | `false`         | Becomes `--network none`                             |
| `readOnly`       | `true`          | Root FS read-only; `/tmp` and `/workspace` are tmpfs |

`SandboxRunner.kill(id)` and `killAll()` are exposed for shutdown; running containers are tracked in `runningContainers: Map<string, ChildProcess>`.

### Sandbox Env Vars

Configured via `process.env` in `src/lib/skills/builtins.ts`:

| Env Var                           | Default          | Purpose                                                            |
| --------------------------------- | ---------------- | ------------------------------------------------------------------ |
| `SKILLS_MAX_FILE_BYTES`           | `1048576` (1 MB) | Cap for `file_read` and `file_write`                               |
| `SKILLS_MAX_HTTP_RESPONSE_BYTES`  | `256000`         | Cap for `http_request` response body                               |
| `SKILLS_MAX_SANDBOX_OUTPUT_CHARS` | `100000`         | Cap for stdout/stderr returned to the caller                       |
| `SKILLS_SANDBOX_TIMEOUT_MS`       | `10000`          | Default timeout for sandboxed commands; capped at 60 s             |
| `SKILLS_SANDBOX_NETWORK_ENABLED`  | `false`          | Master gate for egress. Set `1` or `true` to allow per-call opt-in |
| `SKILLS_ALLOWED_SANDBOX_IMAGES`   | (see below)      | Comma-separated allowlist of Docker images                         |

Default allowed images: `alpine:3.20`, `node:22-alpine`, `python:3.12-alpine`. Any additions via `SKILLS_ALLOWED_SANDBOX_IMAGES` are merged with the defaults; unknown images are rejected by `normalizeImage()`.

> Note: there is no separate `SKILLS_EXECUTION_TIMEOUT_MS` env var. The non-sandbox handler timeout is hard-coded to 30 s in `SkillExecutor` (`executor.ts:13`) but can be overridden at runtime via `skillExecutor.setTimeout(ms)`.

### Workspace Isolation

`file_read` and `file_write` resolve every path relative to a per-API-key workspace at `<DATA_DIR>/skills/workspaces/<sha256(apiKeyId).slice(0,24)>/`. Path traversal (`..`) and forbidden segments (`.env`, `.git`, `.ssh`, `.omniroute`, `.codex`, `secrets`) are rejected before any disk I/O.

### HTTP Hardening

`http_request` (`builtins.ts:257`):

- Method allowlist: `GET, HEAD, POST, PUT, PATCH, DELETE`
- Blocked outbound headers: `host, connection, content-length, cookie, set-cookie, authorization, proxy-authorization`
- Redirects disabled (`allowRedirect: false`)
- Routed through `safeOutboundFetch` with `guard: "public-only"` (private/loopback ranges blocked)
- Response truncated at `SKILLS_MAX_HTTP_RESPONSE_BYTES`; client sees `truncated: true`

---

## Hybrid Executor (preview)

`src/lib/skills/hybrid.ts` defines a `HybridExecutor` that decides between `direct` (in-process) and `sandbox` execution per call, with an `autoUpgrade` retry path on timeout/memory errors. The wired-in `directExecutor` / `sandboxRunner` implementations are stubs (`executeDirect`, `executeInSandbox` return placeholder objects) — treat this module as a contract under construction. Real execution still goes through `skillExecutor` + `SandboxRunner`.

---

## Storage

Schema lives in two migrations:

- `src/lib/db/migrations/016_create_skills.sql` — base `skills` and `skill_executions` tables, with indexes on `(api_key_id, name)` and `(skill_id, status, created_at)`.
- `src/lib/db/migrations/027_skill_mode_and_metadata.sql` — adds `mode`, `source_provider`, `tags` (JSON), `install_count` to `skills`.

`skill_executions.status` is constrained at the database level: `CHECK(status IN ('pending', 'running', 'success', 'error', 'timeout'))`.

---

## REST API

All endpoints live under `src/app/api/skills/`. Management endpoints (`/api/skills`, `/api/skills/[id]`, `/api/skills/install`) require **management auth** via `requireManagementAuth()`. The marketplace/install flows use the lighter `isAuthenticated()` (session or API key).

| Endpoint                          | Method | Purpose                                                                  |
| --------------------------------- | ------ | ------------------------------------------------------------------------ | --- | ------------------------ | -------- | ------------------ |
| `/api/skills`                     | GET    | List registered skills. Supports `?q=`, `?mode=on                        | off | auto`, `?source=skillsmp | skillssh | local`, pagination |
| `/api/skills/[id]`                | PUT    | Update `enabled` or `mode`                                               |
| `/api/skills/[id]`                | DELETE | Unregister by id                                                         |
| `/api/skills/install`             | POST   | Install a custom skill (handler code + schema)                           |
| `/api/skills/marketplace`         | GET    | Search the SkillsMP catalog (returns popular defaults when `q` is empty) |
| `/api/skills/marketplace/install` | POST   | Install a SkillsMP skill (requires active provider = `skillsmp`)         |
| `/api/skills/skillssh`            | GET    | Search the skills.sh catalog (`?q=&limit=`, capped at 100)               |
| `/api/skills/skillssh/install`    | POST   | Install a skills.sh skill (requires active provider = `skillssh`)        |
| `/api/skills/executions`          | GET    | Paginated execution history (`?apiKeyId=`)                               |
| `/api/skills/executions`          | POST   | Execute a registered skill ad-hoc                                        |

The `POST /api/skills/executions` endpoint returns HTTP `503` with `{ error: "Skills execution is disabled..." }` when `settings.skillsEnabled === false` (`executor.ts:42-45`). Operators can flip the master switch from **Settings → AI**.

### Example: install a custom skill

```bash
curl -X POST http://localhost:20128/api/skills/install \
  -H "Authorization: Bearer $OMNIROUTE_MGMT_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "reverse-text",
    "version": "1.0.0",
    "description": "Reverses a string",
    "schema": {
      "input":  { "type": "object", "properties": { "text": { "type": "string" } }, "required": ["text"] },
      "output": { "type": "object", "properties": { "reversed": { "type": "string" } } }
    },
    "handlerCode": "echo-handler",
    "apiKeyId": "your-api-key-id"
  }'
```

The `handlerCode` string is a **handler name lookup** — not executable code. The executor maps it via `skillExecutor.registerHandler(name, fn)` (`executor.ts:25`). Marketplace installs store the SKILL.md text in this field as documentation and route execution through model-generated tool calls. Arbitrary user-supplied source is not eval'd.

---

## MCP Tools

Four MCP tools wrap the skills surface (`open-sse/mcp-server/tools/skillTools.ts`). They are auto-registered when the MCP server boots.

| Tool                          | Description                                                  |
| ----------------------------- | ------------------------------------------------------------ |
| `omniroute_skills_list`       | List skills, optional filters: `apiKeyId`, `name`, `enabled` |
| `omniroute_skills_enable`     | Enable/disable a skill by `skillId`                          |
| `omniroute_skills_execute`    | Execute a skill with an input payload                        |
| `omniroute_skills_executions` | Recent execution history (default 50, max 100)               |

See [MCP-SERVER.md](./MCP-SERVER.md) for transport setup and scope assignments.

---

## A2A Integration

`src/lib/skills/a2a.ts` exports the `memory_aware_routing` A2A skill descriptor and a `registerA2ASkill(registry)` helper. Custom A2A skills live in `src/lib/a2a/skills/` and are dispatched via `A2A_SKILL_HANDLERS` (`src/lib/a2a/taskExecution.ts`). See [A2A-SERVER.md](./A2A-SERVER.md) for the full task lifecycle.

---

## Adding a New Built-in Skill

1. **Define the handler** in `src/lib/skills/builtins.ts` (or a sibling file under `src/lib/skills/builtin/`). Signature: `(input, { apiKeyId, sessionId }) => Promise<output>`.
2. **Sandboxed code path?** Call `sandboxRunner.run(image, command, env, sandboxConfig({...}))`. Use `normalizeImage()` against the allowlist.
3. **Filesystem path?** Always pass through `resolveWorkspacePath(input, context)` before touching disk.
4. **Network call?** Use `safeOutboundFetch` with `guard: "public-only"`; sanitize headers via `sanitizeHeaders()`.
5. **Register** by adding the entry to `builtinSkills` (or calling `registerBrowserSkill(executor)`-style at boot).
6. **Wire built-in tool aliases** (optional) in `BUILTIN_TOOL_ALIASES` (`interception.ts:23`) if the upstream model emits a different name.
7. **Tests** in `src/lib/skills/__tests__/` (Vitest).

---

## Adding a Custom (Non-Builtin) Skill

1. Register the handler at process startup:
   ```ts
   skillExecutor.registerHandler("my-handler", async (input, ctx) => { ... });
   ```
2. Insert the skill via `POST /api/skills/install` (the `handlerCode` field must match the registered handler name).
3. Toggle `mode` to `on` or `auto` via `PUT /api/skills/[id]`.

---

## Operational Tips

- **Master switch:** `settings.skillsEnabled = false` blocks all execution and returns HTTP `503` on `/api/skills/executions`. The registry continues to load.
- **Lock down egress:** keep `SKILLS_SANDBOX_NETWORK_ENABLED` unset (default) for fully air-gapped sandboxing. Per-call `networkEnabled: true` still requires the master gate.
- **Allow specific images:** set `SKILLS_ALLOWED_SANDBOX_IMAGES="myorg/sandbox:1.0,node:22-alpine"` to extend the allowlist.
- **Audit executions:** `/dashboard/skills/executions` and `omniroute_skills_executions` both query `skill_executions`. Successful runs include `durationMs`; failures include `errorMessage`.
- **Cache invalidation:** call `skillRegistry.invalidateCache()` after manual DB edits; otherwise wait 60 s.
- **Anonymous workspace:** when `apiKeyId` is empty, all calls hash to the same `"anonymous"` workspace — share-aware code should always pass a real key.

---

## See Also

- [MCP-SERVER.md](./MCP-SERVER.md) — MCP tool registration and transports
- [A2A-SERVER.md](./A2A-SERVER.md) — A2A task lifecycle and skill dispatch
- [USER_GUIDE.md](../guides/USER_GUIDE.md#-skills-system) — user-facing introduction
- [ARCHITECTURE.md](../architecture/ARCHITECTURE.md) — request pipeline and component map
- Source: `src/lib/skills/`, `src/app/api/skills/`, `open-sse/mcp-server/tools/skillTools.ts`
- Tests: `src/lib/skills/__tests__/integration.test.ts`
