Horizon Chart

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

Annotations already provide readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds only that the tool shows 'each planet's altitude and azimuth', which is marginal behavioral context. No permission or limitation details are given beyond what annotations convey. No contradiction with annotations.

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 description is concise: two sentences plus metadata and an example. The main purpose is front-loaded. The metadata block (group, cost) is useful but could be integrated. The example is helpful but adds length. Overall, efficient for the information provided.

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 11 parameters, no output schema, and no parameter descriptions, the description is incomplete. It does not explain the return format beyond 'altitude and azimuth', nor does it clarify the role of optional parameters like 'houseSystem' or 'zodiacType'. An agent would lack essential context for effective use.

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?

With 0% schema description coverage, the description must explain parameters but only provides an example request body. It does not describe the meaning or purpose of any parameter (e.g., houseSystem, zodiacType). The example helps infer usage but does not add semantic value beyond the raw schema.

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 the tool's function: 'Calculate the horizon chart showing each planet's altitude and azimuth relative to the observer's local horizon at birth.' It uses a specific verb ('calculate') and identifies the resource ('horizon chart') with explicit output details. This distinguishes it from sibling tools like 'local_space' or 'chart'.

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 provides no guidance on when to use this tool versus alternatives. It lacks any mention of preferred use cases, restrictions, or comparisons with related tools such as 'acg' or 'local_space'. The only additional context is the group label 'Astro-Geography', which hints at domain but is insufficient.

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