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

Annotations already declare destructiveHint=true and idempotentHint=true, and the description adds valuable context: it is idempotent (unmarking never-marked is not an error) and it lowers the user's score, which is a behavioral consequence not captured in annotations. It also advises confirmation before removing items the user did not name, which is actionable guidance. The description does not contradict 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 description is three sentences, each with a distinct purpose: defining the action, specifying input formats, and noting idempotency and a caution. It is front-loaded with the core verb and resource, and every sentence earns its place. No fluff or repetition.

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 two-parameter tool with full schema coverage and annotations covering idempotency and destructiveness, the description is nearly complete. It adds the score-lowering consequence and the confirmation advice, which are important for an agent to know. The only minor gap is that it doesn't describe the return value, but there is no output schema and the tool is simple enough that this is not a critical omission.

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%, so the schema already documents both parameters (region and country). The description adds a bit of meaning by explaining that region can be an id or a name, and that country is used to disambiguate names used in several countries. This is helpful but not extensive; the schema already covers the core semantics, so a baseline 3 is appropriate.

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 clearly states the tool's function: 'Unmark a state, province or département, undoing add_region.' It specifies the resource (region) and the action (unmark/remove), and distinguishes it from siblings like remove_country and remove_place by focusing on regions. The mention of 'undoing add_region' further clarifies its relationship to a sibling tool.

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 explicitly explains when to use this tool: to unmark a region, and provides the accepted input formats (region id or name plus country). It also gives a clear exclusion: 'Unmarking something that was never marked is not an error,' which prevents unnecessary calls. It does not explicitly name alternatives, but the sibling list and the 'undoing add_region' phrasing imply the alternative is add_region, which is sufficient.

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