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

Annotations already convey read-only, idempotent, and open-world behavior; the description adds meaningful context by explaining the two output formats and the important caveat that large molecules, mixtures, and some salts may have no 3D coordinates. It does not cover error behavior or rate limits, but those are less critical given the read-only hint.

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 three-sentence description is tightly front-loaded, beginning with the core operation and data returned, then explaining format behavior and availability limits. Every sentence earns its place and there is no redundant restatement of schema details.

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?

For a read-only retrieval tool with a rich output schema and complete parameter documentation, the description covers purpose, format choice, and a key failure-prone case. Truncation and safe-line details are already handled in the parameter schema, so nothing essential is missing.

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?

All six parameters are fully documented in the schema with defaults, enums, and truncation behavior, so the description is not required to compensate. The description briefly reinforces the format distinction and alternate conformer option but does not add substantial parameter semantics 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?

States a specific verb and resource: retrieving a compound's default 3D conformer with atomic coordinates and bonds for one CID. The format distinction (JSON vs raw SDF) further clarifies exactly what the tool returns, setting it apart from sibling compound detail and image tools.

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?

Gives clear use context, such as raw SDF for docking, rendering, or conformer tools, and warns that some compounds lack computed 3D coordinates. However, it does not explicitly name sibling alternatives or state when to prefer them, leaving routing decisions mostly implicit.

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