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

Goes well past the annotations by disclosing upload mechanics (HTTP PUT of raw bytes, ready-to-run curl commands in the response), a 2-hour URL TTL, and replacement semantics via re-PUTting to the same slot. It also explains the downstream consequence of the screenshot choices (headlines are generated from what is on screen), which no structured field conveys.

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 tight paragraphs in execution order: create slots, what to capture, how to upload, what to call next. Every sentence carries actionable information and the tool's role is front-loaded.

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?

No output schema exists, and the description compensates by explaining what comes back (per-screenshot URLs plus curl commands) and what to do with it. For a one-parameter, non-destructive setup tool, nothing an agent needs 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?

Schema coverage is 100% and the single parameter already documents the 1-10 range and the 3-8 sweet spot, so the description only adds framing about what the count represents (distinct core features). Useful but not a large increment over the schema.

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 ('Start a screenshot set and get one upload URL per screenshot') and pins its position in the workflow ('Step 1 of 3'), which is enough to separate it from generate_screenshot_set without opening either schema.

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?

Explicit about what to supply (one screen per core feature, realistic content, in user-priority order) and what to exclude (empty states, onboarding walls, permission dialogs, debug banners, lorem ipsum), then names the follow-up tool to call with the returned set_id.

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