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

Annotations already declare the full safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the description need not restate it. The description adds only that output includes near/far sharp limits, which is largely replicated by the output schema, so no meaningful extra behavioral context is contributed.

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 sentences with the computational purpose front-loaded and no redundancy. The trailing list_bundles pointer is marginally useful navigation rather than pure filler, but it is not part of the tool's core job.

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 pure-function calculator with full annotation coverage, a rich output schema, and fully documented parameters, the description is essentially complete. It is slightly thin on when to prefer it over related photographic calculators like depth of field.

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%: coc_mm, aperture, and focal_length_mm all carry descriptions and defaults in the schema. The description adds no units, ranges, or syntax beyond that, so the baseline 3 applies when the schema does the heavy lifting.

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 names a specific verb (calculate), resource (hyperfocal distance), and the secondary outputs (near/far sharp limits) plus its inputs (lens and aperture). It does not, however, differentiate itself from close photographic siblings such as calculate_depth_of_field or calculate_crop_factor, leaving the boundary to inference.

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?

There is no when-to-use or when-not-to-use guidance and no named alternative tool. The 'See list_bundles' line is a cross-sell pointer to related photography calculators rather than a routing instruction for choosing this tool over a sibling.

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