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

Annotations cover the read-only safety profile, and the description adds real behavioral detail beyond them: the default truncation at "Optional below this line", what full=true unlocks, and what demo=true unlocks. It does not describe output size (e.g., how large the HTML source can be), but the defaults and expansion behavior are well disclosed.

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 payload contents, then the default/flag behavior. Sentences are dense and telegraphic but each carries information; the trailing colour/font instruction is slightly out of place for a retrieval tool description but still actionable.

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?

No output schema exists, so the description must characterize the return — it does so with a concrete content checklist plus the truncation default. Complete enough to call correctly; only the absence of id-source guidance (how to get a valid piece id) leaves a small gap.

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 coverage is 50% (id and full lack descriptions), so the description must compensate — and it does, explaining full=true and demo=true in terms of what content is added. The image parameter's default is only carried by the schema, and id semantics are assumed rather than stated.

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+resource ("spec for one piece") and enumerates what the brief contains (structure, counts, sizes, motion timing, states, hit targets, acceptance checklist). It is clearly distinct from search_pieces/get_family, though it never names those siblings explicitly.

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?

Usage is implied: fetch when you already have a piece id and need the spec. There is no explicit when-to-use vs when-not, and no mention of using search_pieces to obtain the id or get_family to see the surrounding context.

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