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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower; the description still adds the deterministic computation method and, usefully, the pricing tier ('20 credits (Tier 2)') and endpoint, which help an agent decide whether to invoke it. Return-shape detail is absent but an output schema exists.

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?

A single front-loaded sentence carries the purpose and method, followed by terse bracketed metadata for group, endpoint and cost. No filler, no repetition.

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 an output schema, full annotation coverage and 100% schema descriptions on all three parameters, the definition is nearly self-sufficient — purpose, method, cost and endpoint are all present. The remaining gap is sibling disambiguation among the specialized chart tools and reconciliation of the harmonic range mismatch.

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 the baseline is 3 — the birth-data body, timezone, house system and compact-mode fields are all thoroughly documented in the schema itself. The description adds only 'the given harmonic number', and its stated range 'H2–H36' conflicts with the schema's allowed maximum of 180, which could needlessly discourage valid higher harmonics.

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 ('calculate'), a specific resource ('harmonic chart'), and even the underlying algorithm (multiplying all planet longitudes by the harmonic number), which makes the tool's identity unambiguous. It does not, however, distinguish itself from the other specialized-chart siblings (draconic, heliocentric, horizon, vedic_divisional), so an agent must infer the difference from the name alone.

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?

The description only says what it computes; it never says when a harmonic chart is the right choice versus the sibling specialized charts, nor any prerequisite or exclusion. There is no routing guidance at all, just the endpoint and cost metadata.

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