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

Goes well beyond the readOnly/idempotent annotations: discloses the 500-unique-entry processing cap, that response byte limits can return fewer whole entries, the exact resume protocol, and the semantics of deferredCves, withheldCves, previews, and unknown scores. These are non-obvious batch behaviors an agent cannot infer from structured fields.

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?

It leads with the core purpose and then packs pagination, response-partitioning, and alternative-tool guidance into short clauses without filler. It is dense – several concepts per sentence – but every sentence carries operational information for a batch tool.

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, yet the description still explains the response partitioning (deferred/withheld/missing) and how to continue iterating, which is exactly the extra context an agent needs for a paginated batch call. Nothing required to invoke or resume it correctly is left unexplained.

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 is 3, but the description adds real meaning: batchOffset is a resume cursor into first-occurrence normalized unique order, capped at 500 processed entries, and must be paired with the original cves and returned score date. That constrains usage in a way the schema's plain integer description 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?

States a specific verb (retrieve) and resource (FIRST EPSS probability and percentile) for supplied CVEs, and immediately scopes it to either latest or historically dated data. This distinguishes it from epss_get_timeseries (temporal series) and from epss_list_reference, which it names as the coverage/interpretation 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?

Gives concrete operational guidance: resume with nextBatchOffset as batchOffset, resubmit original cves and returned score date, and use epss_list_reference for coverage and interpretation. It does not explicitly say when to prefer epss_get_timeseries or epss_prioritize_cves instead, so the sibling routing is partial rather than complete.

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