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

Annotations already cover read-only, idempotent, and non-destructive behavior, so the description's extra disclosure is commendable. It adds the cost tier (50 credits, Tier 3), the endpoint method, and output cell semantics ('aspect or null'), which are useful behavioral details beyond the annotations. It does not discuss auth or rate limits, but with a rich schema and output schema, this is a reasonable level of transparency.

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 definition is tightly structured and front-loaded: the core output description comes first, followed by compact metadata (group, endpoint, required, cost). Every sentence and tag earns its place with no redundancy or 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 tool with a nested input schema, an output schema, and full annotations, the description supplies the key calling context: required parameters, endpoint, cost, and the default point set. The only notable gap is the absence of guidance on when to choose this over sibling relational tools, but it is otherwise complete enough for correct invocation.

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 schema already documents chart1, chart2, fields, and precision in detail. The description only restates the two required parameters (chart1, chart2) and does not add semantics for fields or precision, which is acceptable given the high schema coverage baseline of 3.

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 clearly states what the tool produces: an NxM matrix of cross-chart aspects between two charts, with the default 13×13 point set and cell contents. It does not explicitly contrast this with sibling tools such as astroway_relational_synastry or astroway_render_aspect_grid, but the resource and output type are specific enough for an agent to understand the core purpose.

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 provides group, endpoint, required parameters, and cost, but gives no guidance on when to use this tool versus alternatives like a full synastry report or a rendered aspect grid. There are no exclusions or conditional recommendations, so the agent must infer usage from the name and basic context.

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