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

The annotations already carry the write/destructive/idempotent hints, and the description adds useful behavior beyond them: append-only semantics, in-place revision when cell_id is reused, the return contract {cell_id, sequence}, and 'costs nothing and builds nothing.' The idempotent hint is clarified by the cell_id revision path rather than contradicted.

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 compact and front-loaded, with every sentence contributing either behavior, usage, constraints, or the return value. The example JSON is directly actionable and earns its place.

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 9-parameter tool with no output schema, the description covers the essential ground: purpose, when to use it, constraints, behavior, side effects, and return value. The remaining gap is the lack of explanation for several optional parameters, but the core decision-recording use case is fully specified.

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?

With 0% schema description coverage, the description partially compensates by explaining the exactly-one run_id/dataset_id constraint, the meaning of cell_id, and by giving an example covering heading, markdown, and phase. However, blocks, revision_of, and checkpoint_seq are never described, and the required parameters are only implied by the example rather than stated.

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 opens with a specific verb and resource: 'Appends one cell to a run's or a dataset's decision record.' It goes on to specify what content belongs in the note and how it relates to the record, making the tool's purpose unmistakable and distinct from the surrounding get/list/run tools.

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?

It tells the agent when to use the tool ('Write one for every decision worth explaining') and states an important precondition ('Exactly one of run_id or dataset_id'). It does not name explicit alternatives or when-not-to-use cases, but there is no obvious sibling that fills this role.

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