Validate App Store screenshot files

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the validation aspects and that it reports gates separately, but does not disclose whether the tool is read-only, what happens on validation failure, if it writes any state, or what the output format is. For a validation tool, it should explicitly state that it does not modify files or require special permissions. This is a significant gap.

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, consisting of two sentences with no wasted words. It front-loads the action ('Validate local screenshot files') and then lists the validation dimensions and the gate reporting. It is easy to parse and not verbose, though it could be slightly better structured with parameter hints, but it meets the conciseness bar.

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?

This tool has 8 parameters, a nested 'expected' object, no output schema, and no annotations. The description is far from complete: it does not explain what the gates are, how the booleans affect behavior, what the return value looks like, or how to handle multiple files. An agent cannot correctly call this tool based on the description alone; it would need to infer from parameter names, which is risky given the lack of documentation. This is severely incomplete.

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 only 13%, meaning most parameters are undocumented in the schema, and the description does not compensate. The description mentions validation aspects but does not map them to specific parameters like 'files', 'slot', 'expected', 'render_manifest', or the three boolean flags. There is no explanation of what 'full_resolution_reviewed' or 'source_fidelity_verified' mean. With such low coverage, the description must clarify parameter semantics, but it offers none.

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 the tool's function: validating local screenshot files for specific attributes (dimensions, format, opacity, readable image data, and deterministic sequence naming) and reporting two gates separately. It names the resource (screenshot files) and the verb (validate), making the core purpose evident. However, it does not explicitly differentiate from the sibling tool 'validate_screenshot_copy', which could be confused for a similar validation task, so it lacks sibling distinction.

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?

No guidance is provided on when to use this tool versus alternatives like validate_screenshot_copy. There is no mention of prerequisites, scenarios where this validation is appropriate, or exclusions. The description only states what it does, not when to invoke it, leaving the agent to infer usage context.

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