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

The annotations already declare destructiveHint=true, but the description adds meaningful behavioral context: changing the SVG affects every part in any style that uses the piece. This cascade warning is valuable beyond the generic annotation and directly informs risk. It does not cover return behavior or partial-update semantics, but the main behavioral trait is 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?

Two short sentences with the core action first and the critical cascade consequence second. There is no filler, and the important caveat is front-loaded enough to influence the agent's decision.

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 destructive mutation with a nested updates object and no output schema, the description covers the main risk but leaves parameter meaning and update behavior partly unexplained. It is adequate but not complete enough to remove ambiguity about what can be updated and how partial updates are handled.

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 for undocumented parameters. It mentions an SVG change, which indirectly maps to the nested svg field, but it does not explain pieceId, the name field, or required/nested update semantics.

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?

The description uses a specific verb and resource: 'Update a reusable SVG building-block piece.' It clearly identifies the object being modified, though it does not explicitly contrast this tool with related update tools such as update_part or update_style.

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?

The description explains a consequence of use when a style references the piece, but it gives no explicit guidance on when to choose update_piece over sibling tools. There are no exclusions, prerequisites, or alternative-tool routing.

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