Synastry Element Balance

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 genuinely useful context that annotations cannot: a 50-credit Tier 3 cost and the POST endpoint. It says nothing about latency, batching, or whether results are cached, so it adds moderate rather than rich behavioral context.

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 dense sentence does the descriptive work, followed by compact terse tags for group, endpoint, required fields, and cost. Nothing is padded or repeated; the only small weakness is that the metadata block is a uniform list rather than weighted toward decision-relevant info.

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-value explanation is unnecessary, and the input schema fully documents both nested chart objects. Cost and requirements are disclosed. The remaining gap is routing guidance across a very large sibling set of element/synastry tools, which leaves an agent to guess the right one.

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 heavily documented (timezone vs timezoneOffset, houseSystem letters, invalid short forms), so the description need not restate any of it. The phrase 'each chart and the combined pair' only loosely signals that two independent birth datasets are expected, which the schema already makes clear.

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?

It names the exact resource and result shape: element and modality tallies per chart plus the combined pair, with dominant and missing elements. That is specific enough to distinguish it from a generic synastry tool, but it never explicitly frames itself against close siblings such as astroway_psychological_modern_arroyo_relational_element_map or astroway_psychological_modern_arroyo_element_balance.

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 pick this over the many other relational/comparison tools; the only context is the mechanical 'Required: chart1, chart2' and price line. An agent must infer the use case entirely from the noun phrase.

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