photos_download

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

Annotations carry only openWorldHint, so the description bears the behavioral burden and does well: it discloses the authentication requirement, the filename-collision consequence ('only one copy survives locally' with 'remove'/'skip'), and the all-or-nothing failure mode ('Fails if any item fails to download'). This meaningfully supplements the thin annotation set with no contradiction.

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?

Four dense sentences with zero filler, and the purpose is front-loaded in the first sentence. Each subsequent sentence earns its place: auth requirement, collision warning, atomic failure behavior, and sibling routing. Efficient and well-ordered.

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?

With no output schema and only openWorldHint as an annotation, the description covers the critical decisions: source scope, destination, auth, conflict resolution, failure semantics, and tool routing. The only minor gap is the unspecified success return value, which is of low importance for a download operation whose observable outcome (files in a folder) is self-evident.

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%, so the baseline is 3. The description adds value beyond the schema by explaining why conflictStrategy matters: multiple timeline photos can share the same filename, and the survival consequence ties the enum options to real outcomes. This is semantic context the schema's per-parameter descriptions do not provide.

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+resource+destination ('Download one or more photos from Proton Photos... to a local folder') and scopes the source explicitly (timeline, album, shared-with-me). The final sentence names the sibling it is not (drive_download), making the boundary unambiguous against the photos_upload and drive_download siblings.

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?

Explicitly states when not to use it ('Do not use for regular Drive files') and names the alternative ('use drive_download instead'). The source scoping (timeline, album, shared-with-me) further clarifies the intended context. No routing decision is left to inference.

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