route

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly states the tool has no side effects ('NEVER executes anything'), describes the return shape ('selection (`chosen` / `candidates`)'), and clarifies the limits of `context` to 'light file metadata', preventing misuse. This is strong transparency for a routing-only tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences and every clause earns its place. The first sentence states the core purpose, and the second packs the critical non-execution caveat plus parameter clarifications without unnecessary fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool has an output schema and no annotations, the description covers all key elements: purpose, non-execution behavior, return indication, parameter semantics, and how to proceed with siblings. It is sufficiently complete for an agent to decide when to call it and what to expect.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It does: `task` is the routing input, `context` is clarified as 'optional light file metadata' with `file_path`/`extension` references, and `mode` is explained as overriding the configured auto/ask default. This adds meaningful semantics beyond the bare schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Pick') and identifies the resource ('best tool or skill for `task`'), clearly distinguishing it from executing tools by stating it 'NEVER executes anything'. It also implies a comparison/ranking role via 'ranked by server-side routing config', which separates it from siblings like `call_tool` and `use_skill`.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says when to use the tool (to select a tool/skill for a task) and provides clear alternatives: 'invoke the pick yourself via `call_tool` or `use_skill`'. It also documents optional parameters (`context`, `mode`) and their purpose, giving actionable guidance for invocation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.