list_chains

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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered by structured data. The description's only additional behavioral claim is that the default scope is every object, which duplicates the schema's default. It adds no new behavioral context such as ordering of returned IDs or handling of objects with no chains.

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 sentences, front-loaded with the purpose and followed by the pre-use guidance. There is no filler, no restated name, and no extraneous detail.

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 the description does not need to explain return values, and the annotations cover the safety profile for this read-only tool. With one fully described parameter, the definition gives an agent everything needed to call it correctly. What is missing is minor: nothing about ordering or empty results.

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% and the single parameter already documents 'Object to inspect. Defaults to every loaded object.' The description's parenthetical '(or in all objects)' merely restates that default. Nothing is added about accepted name formats or what happens for an unrecognized object name, so baseline 3 applies.

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: 'Lists the chain IDs present in an object (or in all objects)', including the scope variation (single object vs. all objects). It is clearly different from list_objects or list_ligands, but it never names those siblings to reinforce the distinction, so it stops short of a 5.

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 concrete usage context: call it before interface_view, conservation_view, or 'any tool that needs a specific chain ID'. That is a real prerequisite workflow rather than an implied one. It does not state any when-not-to-use condition or offer alternatives, so it is not a 5.

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