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 one genuinely useful behavioral fact, the billing cost (10 credits, Tier 1), plus the required-parameter list, but says nothing about determinism, rate limits, or how name participates in a birth-date calculation.

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 core purpose is front-loaded in the first sentence, with the second sentence giving the system qualifier. The bracketed metadata lines are terse and skimmable, though the endpoint line duplicates information an MCP client does not need to make a selection.

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 no explanation, and the operation itself is simple. Still, for a tool sitting in a cluster of five near-duplicate life-path variants, the description omits the guidance that would let an agent pick this one confidently, and it leaves the role of `name` unexplained.

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 only 50%: `fields` and `precision` are documented in-schema, while the two required params (`date`, `name`) have no schema descriptions. The description's "birth date (year + month + day, reduced)" partially compensates for `date`, but it never explains why a `name` is required for a life-path calculation, leaving a real ambiguity.

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 and resource ("Calculate the Life Path number") and names the system variant ("Kabbalistic (phonetic)"), which separates it from the Chaldean/Pythagorean/Vedic life-path siblings. However, it does not differentiate from the near-identical siblings astroway_numerology_kabbalistic_strict_life_path and astroway_numks_life_path, so an agent still has to guess among those.

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?

There is no when-to-use or when-not-to-use guidance and no mention of the alternative life-path tools in the enormous sibling set. The only routing signal is the system label baked into the name and description, leaving the strict vs phonetic distinction to inference.

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