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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds valuable behavior beyond annotations: the paging mechanism via cursor with same recid/index, the index file limit (~1,500 files per index), and the tape/on-demand requirement to request files on the portal before download. This is meaningful operational context not present in the annotations.

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 dense sentences that front-load the primary purpose and then describe the mode split and the on-demand tape caveat. There is almost no waste, though the enumeration of every returned field is lengthy and partly redundant with the output schema, slightly reducing conciseness.

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 tool is relatively complex (4 params, paging, index modes) and the description plus schema plus output schema cover most needs. It explains the index/no-index behavior, paging cursor usage, and the on-demand availability caveat. Minor gaps remain, such as error behavior or how the ~1,500-file index grouping affects paging, but these are not critical for correct invocation.

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%, with detailed per-parameter descriptions (index exact match and .txt-to-.json handling, limit 1-500, recid pattern, cursor semantics). The description mentions the index mode but does not add syntax or format details beyond the schema. A baseline 3 is appropriate because the schema fully documents parameters.

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 specific verb and resource ('List one record's files') and immediately enumerates the return contents (indexes with XRootD URI-list URLs, per-file XRootD URI, HTTPS URL, size, adler32, availability). This clearly distinguishes it from siblings like get_records and search_records, which operate at the record level rather than the file level.

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?

It explains the two modes: 'Without index, returns the record's indexes and its regular files; with index, reads only that index and pages through its files.' This is useful conditional guidance tied to the index parameter. However, it does not explicitly name alternatives or state when not to use this tool (e.g., to find a record, use search_records).

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