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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered, and the description's 'WRITE:' prefix is consistent with them. It adds real context beyond the annotations: the exact-match requirement for wildcard entries and the underlying DELETE endpoint. It does not say how a non-blocked or malformed entry is handled, which is the remaining gap.

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 write semantics and the matching constraint front-loaded and the API endpoint as trailing reference. Nothing is redundant with the title.

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 idempotent write with full schema coverage, annotations and no output schema, the description covers purpose, exact-match behavior and the endpoint. Missing only the failure case (number not currently blocked), which is a minor gap given the annotations.

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% and the schema already says 'the blocked entry exactly as it was blocked', so the baseline is 3. The description earns the extra point by clarifying that the value may be either a plain number or the wildcard pattern that was originally blocked, which is not obvious from the parameter name alone.

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?

Specific verb plus resource ('remove a number from the block list'), with the effect on behavior ('so it can call again') and the underlying API call (DELETE /privacy/unblock-number) stated explicitly. The 'WRITE:' prefix and the 'unblock' framing cleanly separate it from the sibling rinkel_block_number without needing its schema.

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 makes the use case unambiguous: undo an existing block so the number can call again, and it warns that wildcard patterns must be supplied exactly as blocked. It never names rinkel_block_number as the counterpart or states what happens if the entry is not blocked, so it stops short of full when/when-not guidance.

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