get_screenshot_text

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

Annotations already cover the safe-read profile (readOnly, idempotent, non-destructive, closed-world), and the description adds real context beyond them: results are cached until screenshots change, a fresh read costs one AI writing credit on Pro+, and the response carries `indexed: false`. The credit cost and caching behavior are exactly the kind of operational detail an agent needs.

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 sentences, front-loaded with the core purpose and no padding. The em-dash explanation of conversion-vs-rank is slightly editorial but still earns its place by clarifying what the returned text is for.

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, the description still discloses return semantics (`indexed: false`), caching lifetime, and credit cost, giving the agent enough to call and interpret the tool. What remains thin is the absence of explicit comparison to sibling listing tools.

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%, so appId and cc are already documented in the schema. The description adds only the loose phrase 'in one storefront,' which loosely maps to the cc parameter but contributes no syntax or default details beyond the schema, making the baseline 3 correct.

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: retrieving the caption text on the first four App Store screenshots in one storefront. This is clear and distinguishable in concept, but it never names a sibling (get_store_page, get_listing_timeline, validate_listing) to route the agent away from the wrong listing-related read.

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?

Usage is implied — call it to inspect screenshot captions — but there is no explicit when-to-use guidance or comparison against the many listing/store siblings. The note that this text affects conversion rather than rank hints at intent but does not tell the agent when this tool is the right pick.

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