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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds genuinely new context: results are ordered newest-first, line-item detail (e.g. Schedule C service providers) is absent from the index, and pdf_url links to the complete filing. It does not discuss rate limits or auth, but the annotation bar is lower here.

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?

Three sentences, each front-loaded and purposeful: mode one, mode two, then the scope caveat about the index. No filler and no repetition of schema content.

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?

With no output schema, the description carries the return-value burden and does so for the ack_id path by listing fields. The ein path's per-filing shape and the effect of limit/pagination are left to the schema, so it is complete enough but not exhaustive.

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 is 3. The description adds meaning beyond the schema by enumerating the returned fields for ack_id (sponsor, plan name/number, participant counts, plan assets, plan type, filing date, PDF URL) and by stating that ein returns history rather than a single record.

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 names a specific verb and resource ('Get Form 5500 filing detail from the DOL EFAST2 index') and explicitly separates its two operating modes (single filing by ack_id vs. full history by ein). The closing note about line-item detail not being in the search index implicitly distinguishes it from the form5500_search sibling.

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 clearly states which parameter selects which behavior ('Pass ack_id for a single filing... Pass ein instead to get a plan sponsor's full filing history'), giving explicit conditional usage. It stops short of naming a specific alternative tool to use instead, so it lacks the when-not/alternative guidance needed for a 5.

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