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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds useful output-shape context (cells contain an aspect or null; default 13x13 covering Sun..Pluto plus nodes, Lilith and Chiron) and a cost signal (50 credits, Tier 3), but says nothing about error behavior or limits beyond what annotations already give.

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?

Two tightly written sentences: the core behavior and its default dimensions are front-loaded, and the group/cost tags are compact structured metadata. Nothing is wasted and nothing important is buried.

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 read-only computed tool with a full output schema and 100% param coverage, the description adequately explains what is produced, and an output schema removes the need to document return values. However, given the crowded relational-tool family and two large nested chart inputs, the absence of any routing or usage guidance leaves it only minimally complete.

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 rich nested chart1/chart2 schemas do the heavy lifting and the baseline is 3. The description's mention of the default body set relates to the output matrix rather than to any input parameter, so it adds little parameter-level meaning beyond the schema.

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 names a specific resource (an NxM cross-chart aspect matrix between two charts) and even specifies the default grid composition, so an agent knows exactly what artifact this returns. It does not explicitly distinguish itself from neighboring relational tools such as astroway_relational_synastry or astroway_relational_synastry_house_overlay, so it stops short of a 5.

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?

There is no when-to-use guidance and no named alternative. With many sibling relational tools (synastry, house_overlay, element_balance, match_score), an agent gets no help deciding when the aspect grid is the right pick versus those overlaps.

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