filedproof.compare_filingsCompare two filings from the same issuer and return source-backed added and removed disclosure blocks. Structural change is not semantic interpretation.
| Name | Required | Description | Default |
|---|---|---|---|
| item | No | Optional filing item such as 1A or 7. | |
| left | Yes | Left SEC accession number. | |
| limit | No | ||
| right | Yes | Right SEC accession number. | |
| identifier | Yes | Ticker, CIK, or exact SEC company name. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds useful context about what is returned (source-backed added/removed blocks) and a semantic scope boundary, but says nothing about pagination behavior, the limit cap, or provenance/confidence of the 'source-backed' output.
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 tightly written sentences with the core action front-loaded and no filler. The second sentence earns its place as a scope caveat, though its phrasing ('structural change is not semantic interpretation') is slightly abstract.
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 five-parameter tool with no output schema, the description should carry more: it omits how the result set is bounded (limit default 100, max 500), how 'item' narrows the comparison, and what an added/removed block looks like. The stated return content partially compensates.
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 80%, so left/right/identifier/item are largely self-documenting and the baseline is 3. The description reinforces the same-issuer constraint tying left and right together, but adds no detail on the 'item' filter or the limit parameter's effect.
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 (compare two filings from the same issuer) and names the output (added and removed disclosure blocks). It does not differentiate itself from close siblings such as check_disclosure_changes or scan_disclosure_changes, so an agent must still infer which comparison tool to pick.
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 precondition 'from the same issuer' and the caveat 'structural change is not semantic interpretation' imply when this tool is appropriate (pairwise structural diff, not semantic analysis). However, no alternative tool is named and there is no explicit when-not guidance against the several sibling change-detection tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.