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

Annotations already declare the operation read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful context beyond that — the cost (20 credits, Tier 2) and the tool group — but says nothing about auth requirements, rate limits, or what the computation returns.

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 compact lines, front-loaded with what the chart is and followed by structured metadata tags (group, cost). Nothing is padded, though the metadata is arguably redundant with structured tool fields rather than description prose.

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, for a 15-parameter chart tool sitting among fifteen near-identical varga siblings, the description omits the birth-data requirement and any differentiation guidance, leaving real gaps 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?

Schema description coverage is only 33% across 15 parameters, so the description is expected to compensate and does not: it explains none of date, time, latitude, longitude, city, name, zodiacType or houseSystem. The handful of well-documented params (fields, ayanamsa, timezone, precision, timezoneOffset) carry their own text in the schema, so the description adds zero parameter meaning.

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?

The description names the specific artifact (Vimsamsa / D20 chart) and its interpretive domain (spiritual progress, sadhana, religious inclination), which is enough to separate it from the D9/D10/D60 varga siblings on meaning rather than just on the number. It never uses a verb like 'compute' or states that it derives the chart from birth data, so it stops short of a full 5.

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?

Usage is only implied: the parenthetical domain hint ('spiritual progress, sadhana, religious inclination') is the sole signal for when an agent should pick D20 over the other fourteen varga tools. There is no explicit when-to-use statement, no prerequisites (birth date/time/coordinates are only discoverable from the schema), and no named alternative.

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