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

Goes beyond the annotations by disclosing real side effects ("The lesson is then marked applied and links to what it became") and an auth requirement ("Needs permission to change tasks"). It also clarifies that asRule only *proposes* — a human decides — which is important behavioral context the annotations do not carry. It does not address re-invocation/duplicate effects despite idempotentHint=false.

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 core action and effect, then the two modes, then the side effect and permission note — a logical order with no filler sentences. The em-dash interludes make it dense, but every clause carries information.

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-param mutation tool with no output schema, it covers the important ground: what gets created in each mode, that the lesson is marked applied, and the permission gate. What's missing is failure/idempotency behavior (calling twice, or applying an already-applied lesson), which matters given idempotentHint=false.

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 already 83% (baseline 3), and the description adds genuine meaning on top: asRule "proposes a rule (a decision with standingRule, status proposed)" and that the agent "never decides it" — details absent from the schema. noteBody/ruleText/noteCategory get no added semantics beyond the schema text.

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+resource ("Apply a lesson") and immediately names the observable outcome: "it changes how the work is done from now on." That effect distinguishes it from add_lesson (create), update_lesson (edit), and the raw add_context_note/add_decision siblings, which create those artifacts directly rather than deriving them from an existing lesson.

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?

Explicitly covers when each mode applies: asNote for "a fact or a trap," asRule for something "a person must decide it before it binds; you never decide it," and "Either or both." It gives clear conditional guidance but never names an alternative tool (e.g., when to use add_context_note directly instead), so it stops just short of full when-not coverage.

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