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

With no annotations, the description carries the burden well: it discloses the side effect of reusing a slug (bumps `seen`, which feeds graduation into an automatic check), warns against deletion of refuted patterns, and imposes a hard privacy constraint about client data. It stops short of describing what a write returns or any permission/ownership requirements, 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?

Front-loads the action and the cross-site payoff, then gives trigger criteria, the update mechanism, the privacy prohibition, and the sibling routing rule. Dense but every sentence carries a distinct instruction with no filler.

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 6-parameter mutation tool with no annotations and no output schema, the description covers purpose, trigger, update semantics, safety constraints, and routing. Only the absence of any return-value or failure-mode indication leaves a small 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?

Schema coverage is 100%, so the baseline is 3; the description adds meaning beyond schema by explaining that reusing an existing slug performs an update and increments `seen`. It also clarifies the intended content of the body (reusable lessons, not client specifics), which the schema's markdown field outline alone does not convey.

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 ('Write what you learned into the CROSS-SITE knowledge base') and explicitly differentiates from the nearest sibling: 'Use record_action for what you did on THIS site; use kb_record for what it teaches about any site.' An agent can route between the two without opening either schema.

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?

Gives explicit call conditions ('when you found something reusable: a root cause, a probe op that turned out to be decisive, a fix that did NOT work, or a false positive') plus the update path via slug reuse, and names the alternative (record_action) with a clear dividing rule.

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