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

Annotations already establish readOnly, idempotent, non-destructive, closed-world behavior, so safety is covered. The description adds genuine methodological context (Krishnamurti 1971 Vimshottari proportional sub-divisions) and the cost tier (20 credits, Tier 2), but says nothing about output volume, caching, or precision behavior for a 15-parameter tool.

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 tightly written sentences with the resource stated first and the methodological note second, plus compact Group/Cost tags. No filler, though the closing metadata block is boilerplate rather than descriptive content.

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-value explanation is unnecessary, and the description does convey the shape of the result (12 cusps, four sub-lord levels). It remains incomplete on the two things that matter for this tool: when to prefer it over sibling KP endpoints and how the many undocumented input parameters should be set.

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 only 33% across 15 parameters, so the description carries the burden and fails to help: it explains no parameter at all. The only implicit guidance is that 'Placidus' and 'KP-canonical' hint the houseSystem and ayanamsa values, which an agent must still derive from enums.

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?

Names a specific resource and scope: the 12 KP-canonical Placidus cusps, each with a four-level sub-lord chain, and attributes the method to Krishnamurti 1971. An agent can distinguish this cusp-level output from sibling KP tools such as vedic_kp_sub_lords or vedic_kp_asc_sub by inference, though no sibling is named 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?

The description states what is returned but never says when to choose this over the other KP endpoints (sub_lords, sub_sub_lord, planet_cuspal_position, asc_sub). There are no prerequisites, no exclusions, and no routing guidance despite a dense cluster of near-identical siblings.

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