run_drc

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

With no annotations, the description carries the load and does disclose non-obvious behavior: it dispatches to different backends with different mechanics, and the KiCad path reads the board file on disk rather than in-memory state. It does not state that the operation is read-only or whether it blocks, but the disclosure of the on-disk caveat is meaningfully beyond the schema.

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?

Front-loaded with the action, then backend dispatch details, then return shape — every sentence carries information. Slightly dense with backtick-quoted CLI names but nothing gratuitous.

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?

Output schema exists, so the brief mention of violation counts and normalized list is a bonus rather than a necessity. Covers the key prerequisite and the cross-backend behavioral split; the only real hole is the unresolved `backend` value domain.

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% for the single `backend` parameter, so the description must compensate. It only says '`backend` targets one tool in "both" mode', which hints at the semantics but never names valid values or the default behavior, leaving the agent to guess accepted strings.

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?

States a specific verb and resource ('Run geometric design-rule check (DRC)') and scopes it to 'the open board'. It never names the near-identical siblings (pcb_run_drc, pcb_get_clearance_violations, run_erc), so an agent cannot tell from the description alone which of those to pick.

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?

Adds one real prerequisite ('save pending edits first for current results'), which is genuine usage guidance for KiCad. But it gives no when-to-use / when-not guidance relative to the other DRC and violation-listing tools in the sibling set.

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