structure_info

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely useful behavior the annotations cannot express: the RCSB lookup is best-effort and is skipped silently when the object name is not a PDB entry or the API is unreachable, which tells the agent to expect partially populated results. It does not mention latency or any failure when obj_name does not exist.

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 purpose is front-loaded in the first sentence, the content is enumerated once, and the caveat about best-effort metadata is placed last as a qualifier. Every sentence carries information; nothing is repeated from the schema or annotations.

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 return shape need not be spelled out, and the degradation path for missing metadata is documented. The only gap for a simple read-only query tool is what happens when obj_name refers to no object at all.

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 baseline would be 3, but the description adds meaning: the object-name-to-PDB-entry matching rule explains why metadata may be absent, and it implicitly justifies the pdb_id override for renamed objects. This ties the two parameters together in a way the schema does not.

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 states a concrete verb and resource ('summarises what a loaded structure actually is') and enumerates the content returned: chains, residue/atom counts, ligands, symmetry, plus RCSB title, method, resolution, release date and source organism. That makes it clearly distinct from a narrow sibling like count_atoms or list_chains. It stops short of naming a sibling outright, which is why it is a 4 rather than 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?

'Answers the question you ask before any analysis' gives a clear temporal placement in a workflow: call this first to orient yourself. There is no explicit statement of when not to use it, nor a pointer to the narrower alternatives (list_ligands, composition_view, map_info) for follow-up questions.

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