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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that by disclosing the authentication requirement ('Requires signing in to AstralRead') and the exact payload returned to the caller.

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 sentences, front-loaded with the verb and resource, with the auth prerequisite kept short at the end. The parenthetical label example ('«Me», a partner's name) earns its place by clarifying return content; nothing is padding.

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 no output schema, the description correctly takes on the burden of describing return fields and the chart_id linkage, plus the sign-in requirement. Minor omissions remain: it does not say what happens with an empty list or whether results are ordered.

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 single optional 'lang' parameter is fully documented in the schema (en/ru pattern, default en). The description adds no further meaning about the parameter, so the baseline of 3 applies.

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?

Specific verb + resource: 'Lists the birth charts saved in the signed-in user's AstralRead account', and it enumerates exactly which fields come back (label, birth date, time, city, chart_id). It does not explicitly contrast itself with the singular sibling 'my_chart', but the mention that it supplies 'the chart_id the other account tools take' helps an agent place it in the workflow.

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?

Clear context is given: it operates on the signed-in user's saved charts and is the source of the chart_id other account tools require, which implies it is the discovery step before chart-specific calls. It stops short of naming an alternative or stating when-not to use it (e.g. versus 'natal_chart' for a computed chart).

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