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

Annotations only say readOnlyHint=false, idempotentHint=true, destructiveHint=false; the description adds real behavioral context beyond that — the run is counted as failed, surfaces as needing attention via notifications and Monitors passing, and 'no message is sent'. It does not say whether the flag is reversible (undo_visual_review exists as a sibling), which keeps it short of a 5. No conflict with the annotations.

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 the scenario and then the consequences. The parenthetical '(notifications, Monitors passing)' is compressed to the point of ambiguity, but nothing is wasted.

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 single-parameter mutation with no output schema and annotations already covering the safety profile, the description supplies the missing piece — the downstream effect of flagging. Only reversibility/undo guidance is absent, which is minor given the sibling undo_visual_review.

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?

One parameter with 100% schema description coverage, and the schema already documents comparisonId with its source ('From get_run visualComparisons[].comparisonId'). The description adds nothing about the parameter, so the baseline 3 applies.

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 ('mark it a failure' on a visual change) and frames the triggering scenario ('The AI review let a visual change pass, but it's actually broken'). It never names the obvious siblings accept_visual_change or ignore_visual_change, so the agent must infer the negative case rather than being routed 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?

The condition for use is clear: the AI review passed a change that is in fact broken. That implies the alternative (accept_visual_change) without stating it, and no explicit when-not condition is given, so the routing is inferable but not spelled out.

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