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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: unknown or unverified mounts require confirmation, and fixed-lens cameras cannot accept interchangeable lenses. It stops short of describing the response shape or what 'confirmation' concretely entails.

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 tight sentences with the core check front-loaded and the two exception rules following. No filler, no repetition of the name or 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 two-parameter read-only check with no output schema, the description covers the important edge cases (unknown mounts, fixed-lens cameras). It could still state the possible verdicts (compatible / incompatible / needs confirmation) but is otherwise adequate for correct invocation.

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 enum is fully documented, so the schema carries the parameter burden. The description adds only the conceptual mapping of 'camera mount' and no format or edge-case detail beyond the schema's own notes, so the baseline 3 applies.

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 gives a specific verb ('Check') and a precise resource pair (rental lens vs. camera mount), which clearly distinguishes it from siblings like check_availability or get_rental_quote. An agent can identify the tool's function without opening the 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?

It implies the usage context (verifying lens/mount fit) and states two conditional behaviors, but never says when to call this versus alternatives such as get_equipment_details or check_availability, nor does it specify ordering in a booking flow. Guidance is implied rather than explicit.

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