> ## Documentation Index
> Fetch the complete documentation index at: https://docs.deeda.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Tools & MCP

> How agents get tools: workflow grants, power profiles, and attaching MCP servers.

**ELI5:** an agent can only touch what its workflow grants. `tools` says
*which* named tools; `tool_policy`/`sandbox_profile` say *how much power*
those tools get; `mcp_server_config` plugs in *external* tool servers.

## Granting tools

```yaml theme={null}
tools:
  required: [fs.read, fs.write, git, probes.run]
  optional: [redaction.scan, merge.request_slot, beam.issue.update, canvas.workpad]
```

`required` tools must be available or dispatch fails; `optional` tools attach
when present. Common deeda tool names: `fs.read`, `fs.write`, `git`,
`probes.run`, `redaction.scan`, `merge.request_slot`, `beam.issue.update`,
`canvas.workpad`. Provider runtimes add their own built-ins (e.g. Claude
Code's bash/read/write/edit/glob/grep/web\_search — see the
[Anthropic page](/harness/providers/anthropic#claude-code-built-in-tools)).

## Power profiles (the blast-radius dial)

```yaml theme={null}
tool_policy: edit        # read-only | edit | full | network
sandbox_profile: edit    # read-only | edit | full | network
```

`tool_policy` scopes the tool surface; `sandbox_profile` scopes
filesystem/network. Omitting both preserves the default (`edit` ≈ workspace
write, no network). `read-only` is the right default for review/research
agents; `network` requires an explicit `sandbox.network` allowlist:

```yaml theme={null}
sandbox:
  workspace_write: true
  network: [api.anthropic.com]
```

## Attaching MCP servers

MCP servers attach **per participant** in multi-agent workflows:

```yaml theme={null}
participants:
  - id: researcher
    runtime_key: gemini-genai-sdk
    method: mcp
    mcp_server_config:
      deeda-think:
        type: stdio
        command: deeda-think-mcp
```

deeda's own MCP server (`deeda-think`) exposes the Think knowledge tools and
attaches automatically when the run payload requests it. Remote MCP servers
are *partial-compatible* on the Anthropic Messages path (connection contract
proven; full remote round-trip not yet probed) — test small before depending
on one.

## When to use what

| You want                       | Use                                                      |
| ------------------------------ | -------------------------------------------------------- |
| Local file/repo work           | `tools.required` + `tool_policy: edit`                   |
| Research with no side effects  | `tool_policy: read-only`                                 |
| External SaaS tools            | `mcp_server_config` on the participant                   |
| Network calls from the sandbox | `sandbox.network` allowlist + `sandbox_profile: network` |

## See also

* [Workflow Schema](/harness/workflow-schema) — exact field shapes
* [Snippets](/harness/snippets#tools) — copy-paste blocks