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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds two pieces of behavior the annotations lack: the required profile:read scope and a prompt-injection warning about untrusted_fields. It says nothing about how a result is conveyed, but the authorization detail is genuinely useful.

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 purpose front-loaded before the scope requirement. The untrusted_fields sentence is arguably boilerplate that reads oddly on a tool with no output schema, but it costs little and is not padded.

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 one-parameter read tool the description is close to sufficient, but with no output schema it should say what the result looks like (a boolean, a status, alternatives when taken), which it omits entirely. The handle format gap compounds this.

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 is a single required parameter with 0% schema description coverage, and the description adds no meaning: no handle format, length limits, allowed characters, or case-sensitivity rules. The schema is a bare string, so the description leaves the caller guessing what constitutes a valid input.

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 states a specific verb and resource ('Check whether a handle is free'), which is clearly distinct from the sibling mutation tool change_handle. It does not explicitly name that sibling, so it falls short of full differentiation.

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?

Usage is implied by the name and by the existence of change_handle, but the description never says when to call this versus change_handle, nor whether an availability check is a prerequisite for claiming or changing a handle. No exclusions or preconditions beyond the scope requirement are given.

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