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

With readOnlyHint and destructiveHint=false already covering safety, the description adds useful behavioral context: answer in plain everyday words, use the user's language, no astrology knowledge is needed, and birth time is optional ('if known'). It still does not describe the return format or length of the reading.

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 purpose is front-loaded, followed by usage triggers and output-style guidance in two efficient sentences. The list of life areas is slightly expansive but still earns its place by clarifying scope.

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?

Given a simple read-only tool with no output schema and fully documented parameters, the description covers purpose, when to use it, and how to phrase the answer. It could be more complete by explaining what the returned reading contains, but it is largely sufficient.

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%, so all three parameters are already documented, including the gender enum's purpose. The description mentions birth date and optional birth time but adds no syntax or usage details beyond the schema; baseline 3 is appropriate.

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 clearly states a specific resource and scope: a personal reading based on birth date and optional birth time. It implicitly distinguishes itself from compatibility_reading and year_ahead_reading by focusing on the individual's life path, love life and career, though it does not name the siblings explicitly.

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?

It gives clear when-to-use guidance: 'when someone asks what their birthday or birth time says about them, wants a birth chart or life reading, feels stuck, or asks about their path, love life or career.' It does not state when not to use it or explicitly redirect to the sibling tools, which keeps it from a 5.

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