photos_download

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

Beyond the openWorldHint annotation, the description discloses critical behavioral traits: authentication requirement, failure behavior ('Fails if any item fails to download'), and the conflict resolution semantics for filenames. This provides deeper insight into how the tool operates, especially the gotcha that multiple timeline photos can share the same filename.

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 concise and well-structured: it states the action and scope, notes authentication, explains a nuanced collision behavior, mentions failure atomicity, and ends with an alternative. Every sentence serves a purpose, and the warning is front-loaded effectively.

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?

The description is highly complete for selecting and invoking the tool, covering purpose, sources, destination, authentication, collision handling, failure mode, and alternative. The only minor gap is the lack of information about the return value on success, which would be typically expected for a download tool without an output 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?

The schema already has 100% parameter coverage, so the baseline is 3. The description enriches the conflictStrategy parameter by explaining the real-world consequence of 'replace' or 'skip' (only one copy survives) and suggesting 'keep-both' to preserve all. This adds valuable meaning beyond the schema's enum description.

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 clearly states that the tool downloads photos from Proton Photos (timeline, album, or shared-with-me) to a local folder, using the specific verb 'download' and identifying the exact resource. It also distinguishes itself from drive_download by explicitly saying not to use it for regular Drive files, making sibling differentiation strong.

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 provides clear usage context by specifying the supported sources and requiring authentication. It also explicitly names an alternative tool ('use drive_download instead') for regular Drive files, giving a clear when-to-use versus when-not-to-use guidance.

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