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

The annotation readOnlyHint: false indicates a write operation, and the description adds the key behavior 'Soft delete only', which clarifies that the deletion is not permanent. It also discloses the authorization requirement. This goes beyond the annotation without contradicting it.

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 description is a single, front-loaded sentence with an important parenthetical. Every word contributes meaning, and it is appropriately sized for the tool's simplicity.

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 simple delete tool, the description covers the essential constraints (author requirement, soft delete) and the schema fully documents parameters. It could mention the effect of deletion or reversibility, but it is sufficiently complete for an agent to use correctly.

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 100%, with both thread_id and session_id already described clearly in the schema. The description does not add parameter-level details, so the baseline of 3 applies; it provides no additional semantic value beyond the schema.

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 the specific verb 'Delete' with the resource 'forum thread', clearly distinguishing it from sibling tools like forum_delete_reply and forum_create_thread. It leaves no ambiguity about what action is performed.

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 states a critical usage condition: 'You must be the thread author.' This gives clear context for when the tool can be used, though it does not explicitly mention alternatives or when not to use it. Still, the author requirement is a valuable guideline.

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