get-selected-photos

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

No annotations are provided, so the description carries the full burden. It discloses that the tool is read-only, that it reads via AppleScript, that it requires Photos.app running with a visible selection, that it requires macOS Automation permission with a one-time system prompt, and that it returns notFound entries for uncheckpointed imports. It also notes the tool never launches Photos itself. This is rich behavioral context, though it could have added details about error behavior or side effects beyond the one-time permission prompt.

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 well-structured with clear sections: 'Use when', 'Returns', 'Do not use when', and a note. It front-loads the trigger phrase and the core purpose. It is slightly verbose in the note about permissions and notFound, but every sentence earns its place by conveying operational prerequisites or output details. A minor deduction for the note being a bit dense.

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 zero-parameter tool with no annotations, the description covers the input source, output shape, error conditions, prerequisites, permission requirements, and relationship to sibling tools. The output schema exists and the description summarizes its key fields without needing to enumerate them. Nothing an agent needs to decide whether to call this tool and interpret its results is missing.

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?

The tool has zero parameters, so the schema is trivially complete. The description adds meaning by explaining what the tool consumes implicitly (the GUI selection) and what it returns (count, photo summaries, notFound). With 0 params, the baseline is 4, and the description fully compensates for the lack of parameters by clarifying the implicit input source.

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 and resource: it retrieves the identities of photos the user has selected in the Photos.app GUI. It clearly distinguishes itself from siblings by naming query, get-photos, get-thumbnail, export, and add-to-album as downstream consumers of its output, and by explicitly saying 'Do not use when' you want to FIND photos by criteria — use query. This is a precise, non-tautological definition.

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 gives explicit when-to-use triggers ('these photos' / 'the selected photos'), explicit when-not-to-use conditions (finding by criteria → query; Photos.app not running / nothing selected → clear error), and names the alternative tool. It also states prerequisites (Photos.app running with a visible selection, macOS Automation permission). This is exemplary usage guidance.

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