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

Annotations cover the safety profile (readOnly, idempotent, non-destructive). The description adds behavioral context beyond annotations: the default placeholder substitution for image data and the note that placeholders are rejected on update — operationally relevant for a read tool feeding a later write.

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?

Two tight sentences, front-loaded with what is returned, then the default behavior caveat. Every clause earns its place.

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?

Covers return contents and the default image-data behavior, which is the main gotcha for this read tool. No output schema exists, so the description carries the return-shape burden — it does this adequately but does not describe structure of the layout JSON or locale keying beyond the one phrase.

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%, so both parameters (set_id, include_image_data) are already fully documented in the schema, including the default and the placeholder rationale. The description mirrors the same fact rather than adding new syntax or format details. Baseline 3 is appropriate.

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 (fetch) and resource (screenshot set) with scope detail: 'in full: every screen's layout JSON plus per-screen translation overrides keyed by locale.' This distinguishes it from sonar_list_screenshot_sets (which lists) and sonar_get_screenshot_set-style siblings, though it doesn't explicitly name those siblings.

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 usage via 'Fetch a screenshot set in full' but does not state when to use this vs sonar_list_screenshot_sets or when you need full data vs a summary. No explicit alternatives named.

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