fp_info

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and a closed world, so the safety profile is covered. The description adds useful content scope (it reports placement geometry 'exactly as KiCad will place it', including pad drill and layers), but says nothing about error behavior for a bad lib_id or how project shadowing affects results.

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?

A single tightly packed sentence with the resource front-loaded and no filler. The enumerated field list is dense but each item earns its place by telling the agent what data is available.

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?

With an output schema present, the description needn't explain return formatting, and the content enumeration plus full schema coverage make the tool callable without ambiguity. Only the routing relative to sibling lookup tools is left unstated.

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 100%; both lib_id and project_path are documented in the schema, including the shadowing behavior of project libraries. The description adds no parameter-level detail beyond that, so the baseline 3 applies.

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 resource (one library footprint) and enumerates exactly what is returned: description, tags, mount type, courtyard size, 3D model, and every pad with its geometry, drill and layers. This is far more specific than the sibling names (sym_info, lib_fetch, lib_search) and lets an agent tell what it will get without opening the schema.

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?

There is no explicit when-to-use statement and no named alternative. The agent is left to infer that this is the footprint-inspection counterpart to sym_info or a deeper alternative to lib_fetch/lib_search, but the description never says so.

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