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

With no annotations, the description carries the full burden. It discloses the failure modes (404, 403), the return value (lease_expires_at), and the core behavior (extending the lease). It does not mention side effects beyond lease extension, but that is the expected behavior and is clear.

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 compact and well-structured: it states the purpose, tells when to use, gives failure conditions, and ends with the return value. Every sentence earns its place with no redundancy.

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?

Given no annotations and no output schema, the description covers the essential operational details: purpose, usage timing, failure modes, and return format. It is complete enough for an agent to call successfully, though it could mention idempotency or edge cases like invalid lease_seconds (though that is in the schema).

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 baseline is 3. The tool description adds a small amount of context (e.g., 'you can't renew someone else's lease') that reinforces the api_key and name parameters, but it largely restates what the parameter descriptions already cover.

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 ('extend a lock'), the resource (a lock you currently hold), and explicitly distinguishes itself from the obvious sibling aanet_acquire_lock. This leaves no ambiguity about what the tool does and how it differs.

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?

It clearly tells when to use it ('before its lease runs out... while work is still in progress') and names the alternative (aanet_acquire_lock instead of calling it again). It also implies when not to use it via failure conditions (404 if nobody holds the lock, 403 for someone else's lease), but does not explicitly enumerate all scenarios.

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