HD Group Overlay

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world, so the safety profile needs no restating. The description adds genuinely useful context beyond that: the endpoint, that the call costs 100 credits at Tier 4, and that a multi-person input set is required. It says nothing about error conditions or input validation, which would be the next valuable layer.

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?

One tight purpose sentence followed by compact bracketed metadata; the what-it-does clause is front-loaded and nothing is padded. The bracketed tags are terse and each carries distinct information rather than prose 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?

An output schema exists so return values need not be described, and annotations cover safety; the cost and endpoint are disclosed. What remains missing for a Tier-4, multi-chart tool is differentiation from sibling HD group tools and any note on the 2-10 participant bound, which the description leaves to the schema.

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?

The only top-level parameter, "inputs", is undocumented in the description and has 0% reported schema coverage at that level; the description only repeats "[Required: inputs]". However the nested item schema carries a very long, explicit description covering date/time formats, latitude/longitude naming, timezone vs timezoneOffset semantics and houseSystem letters, so the effective documentation burden is largely met by the schema itself.

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 and resource ("Calculate a combined HD group overlay chart") plus the output content (collectively defined centers and channels), which tells an agent exactly what it produces. It does not name or contrast against nearby siblings such as astroway_hd_penta or astroway_relational_group_synastry, so an agent must still infer which group tool to use.

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 phrase "for 2 or more people" implies a minimum participant count but gives no when-to-use/when-not guidance and no alternative routing. With several group/compatibility tools in the sibling list (hd_penta, hd_human_design_compatibility, relational_group_synastry), the description leaves the selection decision entirely to inference.

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