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

Annotations declare destructiveHint=true and idempotentHint=true, but the description adds crucial context beyond them: that overrides replace stored values wholesale, that geometry/styling always come from the source layout, that the locale is auto-enabled on the set, and that authorization is required. These are meaningful behavioral facts the annotations cannot convey.

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 dense sentences, front-loaded with the core action and scope. No wasted words. Slightly dense on the fallback constraint before the auth note, but structure is sound.

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 a 3-param, 100%-coverage mutation tool with no output schema, the description covers scope, fallback behavior, side effect (locale auto-enable), and auth. Missing only a destructive-fallout note (whether prior overrides are lost — actually implied by schema 'replaces wholesale') and return-value expectations, which is acceptable given no output schema.

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 baseline is 3. The description adds the semantic that overrides are keyed by layer id and fall back per-field, but the schema already covers locale format, screenshot_id, and the sparse override shape in detail.

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 (write/override) + resource (locale translations for screens in a screenshot set) with clear scope. Distinguishes from sibling sonar_update_screenshot and sonar_get_screenshot_set by naming the translation-override behavior explicitly.

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?

Explains the fallback semantics ('anything not overridden falls back to source') which implies context of use, and mentions auth requirements. But it never names a sibling alternative or states when NOT to use it (e.g., vs. sonar_update_screenshot for base copy). Usage is implied rather than routed.

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