mechanism_kinematics

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

With no annotations, the description carries the full burden and does well: it discloses that results are exact with NO external solver, that it raises on an unknown mechanism or a non-closing link set, and what it returns. It does not explicitly state that the call is side-effect-free/read-only, which would complete the picture.

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 key framing (exact, no solver, gate for the sibling), then organized into per-mechanism bullets. The output-dict enumeration is dense but justified since there is no output schema; minor redundancy in restating the return dict at the end.

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?

For a 13-parameter tool with no annotations and no output schema, the description covers the three mechanism modes, their inputs, return shapes, and error behavior, which is substantial. The unaddressed `n_steps`/`planar` params and the absent read-only statement keep it from a 5.

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, and it largely does: it maps crank/coupler/rocker/ground to 'fourbar', crank_mm/conrod_mm/wrist_offset_mm to 'slider_crank', n_links/joints to 'gruebler', and documents `config` values. However, `n_steps` and `planar` are never explained, leaving two of thirteen parameters undocumented.

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 ('closed-form planar mechanism kinematics') and explicitly positions itself relative to a sibling ('the static pre-check / gate for mechanism_simulate_submit'). An agent can distinguish it from mechanism_simulate_submit without opening a 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?

Clearly frames the tool as a gate/pre-check before mechanism_simulate_submit and tells the agent which `mechanism` value to pick for each analysis. It lacks explicit when-not-to-use guidance (e.g., when to skip straight to the simulate submit), so it falls short of a 5.

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