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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the description only needs to add context beyond that. It discloses the real behavioral cost driver — 50 credits, Tier 3 — and the fact that the response is a single aggregated call, which is genuinely useful for planning. No contradiction with the read-only annotations.

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 response contents are front-loaded in a single dense sentence, followed by four compact metadata tags (group, endpoint, required, cost). Every element earns its place; there is no padding. Minor: the bracketed tag block is functional rather than prose, but it stays tight.

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, return values need not be explained, and required inputs plus cost are stated. For a tool sitting in a dense cluster of six compatibility siblings, the one remaining gap is explicit routing — the description does not say which sibling to pick instead when a user wants only Ashtakoot or a non-Parashara system.

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 chart1/chart2 objects are documented in rich detail (date/time formats, timezone vs timezoneOffset, houseSystem letters). The description only repeats "Required: chart1, chart2," adding nothing about the four top-level parameters (fields, precision) or the nested chart fields. Baseline 3 is correct when the schema does 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 (combined matchmaking response) and enumerates exactly what it returns: Ashtakoot total, threshold, Manglik check for both partners, per-Kuta sub-scores, and a recommendation. This positions it as the superset of the sibling compatibility tools. It stops short of explicitly naming which siblings it subsumes (compatibility_ashtakoot, compatibility_manglik_check), so differentiation is implied rather than stated.

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?

"in one call" strongly implies this is the aggregation shortcut versus calling the individual Kuta/Manglik endpoints, which is usable guidance. However, it never states when NOT to use it — e.g. versus astroway_vedic_compatibility_dashakoota or bhrigu_match, which are different matching systems, not subsets. No explicit alternative is named.

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