structure_info

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

No annotations are provided, so the description carries the full burden. It discloses that metadata lookup is 'best-effort' and 'skipped silently' when the object is not named after a PDB entry or the API is unreachable. This is a meaningful behavioral trait beyond what the name implies. It also clarifies that it combines PyMOL state with RCSB metadata, which sets expectations for output.

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 well-structured: a one-sentence summary, a paragraph detailing what it answers and combines, and a final paragraph on limitations. Every sentence adds useful information, and the main purpose is front-loaded.

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 fully covers what the tool does, what input it expects, and how it handles edge cases (unreachable API, non-PDB-named objects). With an output schema present, the lack of explicit return-value documentation is acceptable. This is complete for a summary tool.

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 coverage is 100%, so the schema already documents both parameters. The description adds value by explaining the purpose of pdb_id as a fallback when the object name no longer matches the PDB entry, and provides an example for obj_name ('1hsg'). This extra context helps select and fill parameters correctly.

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 what the tool does: 'Summarises what a loaded structure actually is, in one call.' This is a specific verb ('summarises') plus a specific resource ('loaded structure') and scope ('in one call'). It distinguishes itself from sibling tools that perform more targeted queries (e.g., list_chains, atom_properties) by offering a holistic summary.

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 clear context for when to use the tool: 'Answers the question you ask before any analysis.' This implies it should be used as an initial inspection step. It does not explicitly name alternatives or exclusions, but the one-call summary framing effectively contrasts with more focused sibling tools.

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