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

Goes well beyond the annotations: accepted formats (JPEG, PNG, WebP), a 3 MB size cap, that hidden metadata (GPS, camera) is stripped, that any existing photo is replaced, and that an organizer key is required. These are non-obvious behaviors an agent could not infer from the schema alone.

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?

A single dense sentence that front-loads the action, then packs format limits, metadata handling, replacement semantics, and auth requirement with zero filler. Every clause earns its place.

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 3-param mutation with no output schema, the description supplies formats, size limit, metadata stripping, replacement behavior, and auth. The only unmet piece is what happens on success/failure (e.g., error on oversized or non-https URL already implied), a minor gap for a setter.

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 only 33% (only 'entry' is described). The description compensates meaningfully by constraining photo_url (https, JPEG/PNG/WebP, up to 3 MB), which the schema only weakly hints at with a ^https:// pattern and maxLength. It does not restate slug or entry semantics, so it is helpful but not exhaustive.

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?

States a specific verb and resource ('Give an entry (or hunt checkpoint) a photo') with the source (public https image URL). No sibling tool touches photos, so it is trivially distinguishable from add_entries, set_questions, update_settings, etc.

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?

Provides the operative context: the photo must come from a public https URL, and the tool 'Needs the organizer key', which is a real prerequisite. It also notes replacement behavior, so an agent knows this is an overwrite rather than an add. It stops short of explicit when-not guidance, but there is no competing sibling for this action.

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