Synastry House Overlay

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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is fully covered. The description adds genuinely useful non-schema context – cost of 50 credits at Tier 3 and the POST endpoint – but says nothing about result shape or interpretation limits beyond 'top-3 emphasized houses'.

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 front-loaded sentence followed by four short bracketed metadata lines; nothing is padded and the key mechanic appears first. The metadata block is compact rather than verbose.

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?

With an output schema present, the description need not explain return values, and it covers purpose, endpoint, required inputs and credit cost. The remaining gap is disambiguation from the large family of relational siblings, which an agent cannot resolve from this text.

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% and both nested chart objects are documented in depth (coordinate formats, timezone rules, house-system letters). The description only repeats the required field names, adding no meaning beyond what the schema provides, so baseline 3 applies.

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 first clause states a concrete verb and mechanism – placing each chart's personal planets into the partner's houses – and names the output (top-3 emphasized houses on each side). That is far more specific than the title, but it never names a sibling tool (e.g. synastry_aspect_grid, synastry_attraction_score) so the agent must infer differentiation from the name alone.

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 statement of when to prefer this overlay over the many other relational/synastry siblings, nor any prerequisite or exclusion. The [Required] and [Cost] lines are operational metadata, not usage guidance.

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