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

Annotations are minimal (only title provided), so the description carries the full burden. It discloses persistence behavior (holds until change or TTL) and override rules, which is helpful. However, it does not mention side effects (e.g., immediate vs. lazy writes), error cases, or authentication needs. The schema covers clearing behavior (empty string clears to General), but the description does not reinforce that. For a mutation tool, more transparency about impacts would raise the score.

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?

The description is two sentences with no dead weight. The first sentence front-loads the purpose and inputs. The second sentence delivers critical behavioral context (persistence, TTL, override). Every part earns its place, and the structure is scan-friendly for an AI agent.

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?

Given no output schema, the description covers necessary context: what the tool does, its scope (writes focus), persistence rules, and interaction with other tools. It does not describe the return value (likely empty or success indication) or error scenarios, but for a simple setter with two optional string parameters, the provided information is largely sufficient. The absence of output documentation is a minor gap, leaving the agent to infer success/failure from implicit convention.

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 the baseline is 3. The description adds minimal value beyond the schema; it merely paraphrases 'knowledge area' and 'project' without providing format examples, constraints, or context about valid slugs. It does not enhance the agent's understanding of how to construct parameter values beyond what the schema already offers.

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?

The description explicitly states the tool sets the operator's write focus by specifying knowledge area and optionally project. It clearly distinguishes from siblings like 'capture', 'commit', or 'note' by being the dedicated focus-setter. It also notes it is called by the wake card's chips, providing context without ambiguity.

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 description explains that the focus holds until changed or idle past TTL, and that explicit area/project arguments on commit/note/handoff take precedence. This gives clear context on when the effect persists and how it interacts with other tools. However, it lacks explicit negative guidance (e.g., when not to use) or direct comparison to sibling alternatives despite having a unique role.

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