ephemeris_composite_midpoint

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

Annotations already indicate readOnlyHint=true and destructiveHint=false. The description adds the credit cost (3 credits) and clarifies the method (midpoints of matching planet positions), providing useful behavioral context beyond the annotations. No contradictions found.

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 extremely concise—two sentences: one for purpose and one for credit cost. No redundant phrases, and the critical information is front-loaded in the first sentence.

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?

The description explains what the tool does, mentions the alternative method, and notes the credit cost. However, it lacks usage context such as when to prefer this composite method over the standard one. Given the high schema coverage and annotations, it is mostly complete but could benefit from a brief usage note.

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?

Input schema covers 100% of parameters with clear descriptions, so the schema already does the heavy lifting. The description adds no extra information about parameters, so it does not enhance semantic understanding beyond the 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 'Calculate a midpoint composite chart' and explicitly labels it as 'an alternative composite method', which distinguishes it from the standard composite tool (ephemeris_composite) among siblings. The verb-resource pairing is specific and unambiguous.

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 explicit guidance on when to use this tool over the standard composite method or other relationship tools. The description only mentions it is an alternative method but does not elaborate on the context or criteria for choosing it, leaving the agent without decision support.

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