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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the repeated 'Read-only' adds little. However, the description adds real context: the return fields (uuid, name, hex_color, role) and the auth scoping 'the signed-in user can access,' which is useful given there is no output schema. Not full marks only because the safety line restates the 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?

The English portion is tight and front-loaded: purpose, returned fields, then the critical session-first guidance. The trailing French translation duplicates the same content rather than adding new information, which is mild waste but does not obscure the front-loaded message.

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, no-input tool with no output schema, the description covers everything an agent needs: what it returns, that it is safe/read-only, that output is scoped to the signed-in user, and that it must be called first to obtain the uuid required downstream. Nothing material 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?

There are zero input parameters, so per the rubric the baseline is 4. Nothing in the description needs to compensate for schema gaps; the field list it provides describes output, not inputs.

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 ('List the PurrPlan workspaces') plus scope ('the signed-in user can access') and the exact fields returned (uuid, name, hex_color, role). It is the only workspace-listing tool among the siblings, so no disambiguation is needed and none is confused.

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?

Explicitly instructs 'Use this first in a session' and gives the reason: 'the uuid is required by almost every other tool, and guessing one fails.' This tells the agent both when and why to call it before the sibling tools, which is exactly the routing guidance that matters here.

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