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 bar is lower. The description still adds real behavioral value: it discloses that it flags when a Lahiri judgment must not be reused and that alternative full derived charts stay explicitly unvalidated, which is meaningful limitation context beyond the 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?

Two tight sentences, front-loaded with the core comparison action before the anchor details and the validation caveat. Dense but every clause carries information; no filler.

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 values need not be described, and annotations cover safety. However, with 10 parameters and zero schema coverage, the description leaves the anyOf location input and timing parameters unexplained, which is a real gap for correct invocation.

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?

With 10 parameters at 0% schema description coverage, the description carries the full documentation burden but documents almost nothing. It references 'topic' and 'selected alternative ayanamsa projections' (conventions), but never explains the place-vs-lat/long/timezone anyOf, timezoneOffset, or the convention enum values, leaving the schema opaque.

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 (compares) and resource (Lahiri vs alternative ayanamsa projections for one topic), and enumerates the anchors it checks (Lagna, topic lord, karaka, sign, house, Nakshatra). It is clear what the tool does, though it never names the close siblings compare_traditions or compare_reading_versions to differentiate itself.

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 phrase 'for one topic' and 'marks when a Lahiri judgment must not be reused' imply the context of use, and the unvalidated-charts caveat hints at boundaries. But there is no explicit when-to-use instruction or routing against the alternative comparison tools, so usage must be inferred.

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