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

Annotations already declare readOnlyHint/idempotent/non-destructive, so the 'Read-only' sentence is confirmatory rather than additive. The description does add real behavioral context beyond the annotations: an account/auth prerequisite, the 6-person ceiling, and the recent-saved fallback when profiles is omitted. It stops short of describing pagination or result ordering.

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 with output content, then usage triggers, then the auth/routing caveat — a sensible order. The final sentence enumerating five sibling tools is long but functional routing information rather than 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?

Without an output schema, the description carries the burden of explaining return values and does so (12 verdicts per person plus chapter/phase). Auth requirements, defaults, limits, and alternatives are all covered, so an agent can select and invoke it without further exploration.

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 coverage is 100%, so the baseline is 3; the description earns a bump by documenting the default path when 'profiles' is omitted, which the schema cannot express (schema requires 2-6 items). It doesn't elaborate further on ids vs names, which the schema already handles.

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 concrete verb and resource ('side-by-side view of up to 6 saved people') and then specifies the exact output shape: 12 life areas rated strong/mixed/needs care via Sarvashtakavarga points, plus current life chapter and phase. This is clearly distinguishable from my_family_phases (phases only) and match_my_profiles (compatibility matching).

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?

Explicit when-to-use triggers are given ('how family members differ', 'who is better placed for something', 'overview of the family'), plus a default-behavior rule ('Omit profiles to compare the 6 most recently saved') and an explicit routing note to sign-in-free alternatives (free_kundli, kundli_milan, explain_dasha, full_chart, life_timeline) when birth details are typed in chat.

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