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

Beyond the annotations (which only say it is a non-read-only, non-destructive, non-idempotent, closed-world write), the description discloses the return artifacts (a project_handle and one upload command in bash and PowerShell forms), the 1-hour upload/finish_project deadline, the 72-hour window for a finished project, that nothing is public, and that no account is needed. This is substantial operational context an agent could not get from the structured fields.

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?

It is a dense single block, but nearly every sentence carries distinct information (environment gating, purpose, return value, deadlines, privacy). It is slightly redundant in repeating the upload/finish_project timing, and the actual purpose statement is buried behind the usage caveat rather than 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?

For an 11-parameter creation tool with no output schema, the description supplies what the structured data cannot: the two return artifacts, the mandatory follow-up call, and both lifecycle deadlines. Combined with 100% schema coverage, an agent has everything needed to invoke this correctly and complete the flow.

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 100% and the schema is unusually rich (per-field constraints, examples, defaults, enum values), so the baseline is 3. The description only restates a few schema facts (1 to 6 screens, store order, screen name plus headline) and adds no syntax or format meaning beyond what the schema already provides.

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 action and resource: "Starts a screenshot set: 1 to 6 screenshots in store order, each with a screen name and a headline," and names the follow-up (finish_project). However, it never distinguishes itself from the sibling make_screenshot_set, so an agent facing both cannot tell which one to pick from the text alone. Clear purpose, but incomplete sibling differentiation.

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?

It gives an explicit precondition ("when you can run shell commands on the user's machine and have their app's screenshots as local files") and an explicit exclusion ("Not for a chat without a terminal, such as ChatGPT, where the upload command cannot run"). It also sequences the workflow (run the upload command once, then call finish_project) with concrete timing windows, leaving little to inference.

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