Model spec format

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

Annotations already declare read-only, idempotent, closed-world behavior, so the safety profile is covered. The description adds substantive context beyond that: it discloses the exact return format (rules, a small-car JSON example, one line per kind with defaults), which is valuable since there is no output schema. No contradiction with annotations.

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?

Three compact sentences, front-loaded with the core purpose, then return shape, then usage routing and alternatives. Every sentence carries distinct value with no filler.

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 zero-parameter, read-only educational tool with no output schema, the description covers purpose, output content, when to call it, when to skip it, and the lighter sibling alternative. Nothing an agent needs to select or use it correctly is missing.

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?

The tool takes zero parameters, so the baseline is 4. The description does clarify that the output documents each ready-made kind's parameters and defaults, which helps an agent understand what spec/param information it will get, though there are no tool arguments to explain.

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 — 'Explain the model spec' — and defines what the spec is: 'a JSON tree of named parts that godot_model_build turns into a .glb.' This distinguishes it from godot_model_build (the consumer) and godot_model_brief (the shorter cheat sheet) without requiring 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?

Gives explicit when-to-use ('Read it before you write a `spec` or pass `params` to godot_model_build') and when-to-skip ('skip it when a ready-made `kind` with its defaults is enough'). It also names the lighter alternative sibling, godot_model_brief, leaving nothing to inference.

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