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 contributes the credit cost (10 credits, Tier 1) and required-input list, which are genuinely useful operational details, but says nothing about output shape or failure behavior.

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?

One tight prose line followed by scannable bracketed metadata (group, endpoint, required, cost). Front-loaded and free of filler, though the metadata partially duplicates structured fields.

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. Combined with annotations covering the safety profile and the description supplying cost, endpoint and required inputs, an agent has enough to invoke it correctly; only the conceptual distinction from sibling readings is unstated.

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?

The bracketed '[Required: name, date]' restates what the schema already enforces, and the two optional compact-mode params (fields, precision) carry their own schema descriptions. At 50% schema coverage the description neither compensates for the undescribed name/date semantics nor adds format hints beyond the schema pattern.

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 four Pinnacle cycles with their age boundaries') plus the system (Chaldean), which distinguishes it from the Kabbalistic, Pythagorean and Vedic pinnacles siblings. It stops short of contrasting the concept against other Chaldean tools such as chart or challenge.

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?

No guidance on when to choose Pinnacle cycles over the many other Chaldean numerological readings (chart, challenge, maturity, personal_year). The only routing signal is the group/endpoint metadata, which tells the agent what family the tool belongs to but not the condition that selects it.

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