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

Annotations grant no destructive/idempotent detail beyond hints; the description adds real behavioral context by noting that auto:all *replaces* existing labels and that the call returns the notebook's whole label set. It also discloses the POST endpoint. Minor gap: it doesn't warn that this is non-idempotent (re-running auto:all re-triggers labeling).

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 three usage modes in one dense sentence, then tacks on two short, high-value sentences (return value, next-step tool, endpoint). The heavy parentheticals make the first sentence a bit packed, 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 4-param write tool with no output schema, the description covers the modes, the key constraint, the return value ('whole label set'), and the follow-up tool. Complete enough to call correctly; only the non-idempotency caveat is missing.

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 baseline is 3, but the description adds meaning beyond the schema: it explains the enum values' effect (all vs. unlabeled) and states the mutual-exclusion constraint between auto and name that the schema's additionalProperties=false does not enforce.

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 (create labels) and resource (source labels) and enumerates the three distinct modes: auto-all, auto-unlabeled, and a named label. It even names the sibling used to fill labels, so an agent can separate this from notebook_update_label 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?

Explicitly frames the when-to-use branch: 'all of them (auto: all, replacing the existing labels) or only unlabeled ones (auto: unlabeled), or create one empty label of your own (name...)'. It also gives the exclusivity rule 'give auto or name, not both' and points to the alternative tool for populating a label.

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