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

Annotations already establish read-only, idempotent, non-destructive, open-world behavior, and the description adds real context: it is a read-only evidence substrate with aggregate reuse state, deliberately not a ranking or materiality judgment. It does not cover auth requirements, cost/latency, or how lineage reuse is triggered.

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, front-loaded with the core action, and the second sentence efficiently explains the return payload and why it exists. The middle sentence is long and clause-heavy, but every clause earns its place.

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 13-parameter tool with no output schema, the description usefully characterizes the return payload (current evidence, transition evidence, reuse state) and the tool's epistemic limits. The gap is that several tuning parameters affecting behavior remain opaque, but an agent has enough to decide when and how to call it.

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?

With 69% schema description coverage, several parameters (history, comparisonLimit, maxArchiveFiles, fingerprintLimit) carry no description anywhere. The description only corroborates the identifiers bound (two to six companies) and the topic concept, adding essentially no syntax or meaning beyond the schema; baseline 3 is the right anchor here.

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 and resource: aligning a disclosure topic across two to six public companies from source-backed historical disclosure lineage, and enumerates the three outputs (current filing evidence, latest same-form transition evidence, aggregate reuse state). It also bounds the tool negatively ('an evidence substrate, not a ranking or materiality judgment'). It stops short of naming the sibling it supersedes (compare_filings / build_disclosure_lineage), so it is clear but not fully differentiated.

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 clear context for use: cross-company alignment of one topic where the caller would otherwise retrieve, parse, align, and re-compare each filing history separately. That implies the alternative (manual or per-company sibling calls) but no sibling is named and no when-not guidance is given.

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