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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description nonetheless adds that data comes 'from its latest live state' and that the returned chart ids and pivot names are the exact handles consumed by the mutation siblings — real behavioral context beyond structured fields. It stops short of covering failure modes (missing file, permission scope) or cost/size of the payload.

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 content is front-loaded with purpose and the usage sentence lands before the enumeration, so the essentials are read first. However, the single mega-sentence with nested parentheticals is dense, and the signature line restates the schema verbatim — a small amount of waste.

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 return values need not be described, yet the description usefully names the key identifiers an agent must carry forward. For a one-param, read-only introspection tool this is nearly sufficient; only the meaning/format of file_uuid and behavior on a nonexistent file are absent.

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 0%, so the description is the only source for parameter meaning, yet it never explains what file_uuid denotes (a workbook identifier vs. a path or URL) or its format. The trailing 'Signature: files_context(file_uuid)' merely restates the required param already visible in the schema, adding no semantics.

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 opens with a specific verb+resource ('Returns structured context about a Tabulya spreadsheet') and then enumerates the four payload groups (sheet schema with A1 ranges, native charts, PivotTables, code-cell dependency graph). This clearly distinguishes it from files_get_info and sheets_list, which an agent could otherwise confuse with it.

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 gives an explicit usage condition: 'Use it to understand a file before reading or editing specific ranges,' and it routes chart/pivot follow-ups to the right siblings (files_update_chart / files_delete_chart, files_set_pivot_table / files_delete_pivot_table). It does not explicitly contrast itself with files_dependencies, files_read_code, or files_get_info, so the when-not guidance is incomplete.

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