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

Annotations already declare destructiveHint=true, idempotentHint=false, and readOnlyHint=false. The description adds value beyond them by disclosing the cascade (saved posts are removed) and the important non-effect (the posts themselves remain in the database), plus a failure mode for parent projects. It stops short of stating that deletion is permanent/irreversible or what permissions are required, which would round it out.

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-loads the action and its main effect, then the refusal rule, in a compact form. The trailing 'Free. Cost: free.' is duplicated filler that adds nothing about the operation.

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 one-parameter destructive tool with annotations covering the safety profile and no output schema, the description supplies everything an agent needs: what is removed, what survives, and the one condition under which the call fails.

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 100% for the single projectId parameter, so the schema carries the burden and the baseline is 3. The description only implies the target ('one of your projects') and adds no format, source, or lookup guidance for the id.

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 ('Deletes one of your projects') and immediately scopes the effect ('together with its saved posts'). It is trivially distinguishable from create_project, list_projects, get_project, and remove_project_posts (which detaches posts rather than deleting the container).

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 a concrete precondition: a project holding sub-projects is refused, and those must be deleted first. That is real when-to-use guidance for a delete operation. It does not name an alternative for the sub-project case (e.g., which sibling to call to delete children), so it is clear context without explicit routing.

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