Match Score (dating compatibility)

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description is not the burden-bearer. It still adds real context the annotations cannot: the exact output payload composition, the input contract ('Same TwoChart input as /synastry'), the endpoint, and a 50-credit Tier 3 cost that matters for call budgeting.

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 first clause front-loads the deliverable and the output inventory, then a second sentence gives the selection rationale. The bracketed metadata block (group, endpoint, required, cost) is compact and skimmable rather than prose padding.

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, yet the description still enumerates what comes back, and it covers input contract, cost, and the specific niche it serves. For a two-param, nested-input, mutation-free aggregate tool, nothing an agent needs to select or invoke it is missing.

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 the nested chart objects are documented in depth (date/time formats, timezone vs timezoneOffset precedence, houseSystem letter encoding), so the schema does the parameter work. The description only adds 'Same TwoChart input as /synastry', which is a contract pointer rather than new parameter semantics; 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?

States a specific verb+resource: an aggregate dating-compatibility score over the synastry engine, enumerating the concrete outputs (0-100 score, label, harmony/tension, attraction components, cross-aspects, flags). It also explicitly positions itself against the alternative path of 'synastry + attraction + their own flag logic', which separates it from siblings like astroway_relational_synastry and astroway_relational_synastry_attraction_score.

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 line 'Built for dating apps that want a single call instead of synastry + attraction + their own flag logic' gives a clear selection rule against the compose-it-yourself alternative. It stops short of naming the specific sibling tools to use when the caller wants only one component, and offers no explicit when-not-to-use condition.

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