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

Annotations already declare this is a non-read-only, non-destructive, closed-world mutation, and the description adds genuinely new facts: it is a state transition only, it does not perform the underlying fix, and it returns the gap. It does not say whether the transition is reversible or whether re-marking an already-done gap errors, which keeps it below 5.

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 short sentences, front-loaded with the action and its precondition; the parenthetical clarification prevents a costly misreading and earns its place. No filler whatsoever.

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 one-parameter mutation with no output schema, the description covers the precondition, the effect boundary, and the return value ('Returns the gap'). Only idempotency/undo behavior on an already-done gap is left unstated, a minor gap.

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?

Single parameter with 100% schema description coverage, including provenance ('from list_knowledge_gaps'), so the schema does the work. The description adds nothing about the gapId beyond what the schema states, which is the expected baseline here.

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 an open knowledge gap done') and scopes it with the precondition that the fix already exists. It implicitly separates itself from fix-creation tools, but never names sibling alternatives such as dismiss_knowledge_gap or update_knowledge_article.

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?

'once its fix is made' gives a real trigger condition for calling the tool, which is more than most mutation tools offer. However, it gives no guidance on the closely related dismiss_knowledge_gap or on what to do if the gap is already done, leaving the competitive choice to inference.

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