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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, closed-world, so the safety profile is covered. The description adds only the cost tier and that it is an alias. It does not explain pagination/cursor behavior (despite 'cursor-friendly' label), and 'Cursor-friendly' is vestigial wording that edges toward contradicting the read-only, non-paginated synastry result. No return-shape or error semantics are provided.

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?

Front-loaded single sentence that names the score and its algorithm, followed by compact metadata lines (group, endpoint, required params, cost) and the alias note. No filler, though the 'Cursor-friendly alias' phrasing is slightly awkward.

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 a present output schema and 100% schema coverage, the description does not need to explain return values. It covers required inputs and cost, but omits usage context vs. sibling score/match tools, which is the main gap for a routing decision among ~600 siblings.

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, housesystem, timezoneOffset, fields and precision in rich detail. The description adds nothing about parameters beyond naming the two charts. Baseline 3 applies when the schema does all the heavy lifting.

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: it produces a weighted 0-100 attraction score from named synastry contacts, distinguishing it from generic siblings like astroway_relational_synastry or astroway_relational_match_score. It does not explicitly contrast with the sibling attraction-score tool or explain how the score differs, but the algorithmic detail and note that it is a cursor-friendly alias are clarifying.

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?

No when-to-use guidance is given. The description names the inputs (chart1, chart2) and notes it is an alias, but never says when to choose this over astroway_relational_synastry_attraction_score or astroway_relational_match_score. An agent must infer selection from the name alone.

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