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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so no safety contradiction exists. The description adds behavioral detail beyond those hints by defining the tool's result as a complete inventory of a single filing, including the full .txt submission; however, it does not describe potential pagination or response-size behavior.

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 contain no filler: the first states scope and content, the second states the immediate downstream use. Every clause earns its place and the key action 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?

For a simple read-only enumeration tool with 2 fully described parameters, an output schema, and covering annotations, the description covers what the tool does and how the output is consumed. The only minor omission is an explicit link to the upstream listing tool (sec_list_filings) that would produce the accession number.

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%, so the baseline of 3 applies; the input schema already documents cik as a company CIK number and accession_no with an example. The description adds no further parameter-level detail beyond implying that the filing is identified by the accession number.

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 pair ('Enumerate every file in a single SEC filing') and enumerates content types (primary document, exhibits, images, XBRL, .txt submission), which clarifies exactly what is returned. It also names the downstream sibling sec_get_filing_document, so an agent can distinguish this indexing tool from the document-retrieval tool.

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 final sentence gives an explicit usage cue: pass a returned file name to sec_get_filing_document. This tells the agent how to use the output and routes it to a specific sibling, but it does not explicitly state when not to use the tool or when to prefer sec_list_filings instead.

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