photos get picker session

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

Annotations already cover safety (readOnly, idempotent, non-destructive), so credit goes to what it adds: the semantics of media_items_set flipping true only after the user finishes picking, plus a rate-governing instruction to honor poll_interval. That is real behavioral context an agent could not get from the structured fields, though failure/expiry states remain undisclosed.

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?

Three short sentences, front-loaded with the action and followed by the completion signal and polling constraint. No filler, though the line-broken phrasing reads slightly like fragments rather than prose.

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?

An output schema exists, so return values need not be explained, and the polling contract is covered. What is missing is the linkage to the sibling tool that creates the session, leaving the agent to infer where session_id and poll_interval originate.

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 0% for the single session_id parameter, so the description would ideally say where that ID comes from. It does not, and instead references poll_interval, which is not present in this tool's schema and must be carried over from the create call — mildly confusing but not harmful.

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 ('Check a Picker session') and adds the completion signal (media_items_set) that defines what a check yields. It is distinguishable from photos_list_picked_media_items, but it never names photos_create_picker_session, which is the tool that produces the session_id being checked.

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?

Implies a polling workflow by instructing to respect poll_interval between checks, which tells the agent this is a repeated-call tool rather than a one-shot lookup. However, there is no explicit guidance on when to stop polling, what to do on failure, or why one would choose this over the sibling list/create tools.

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