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

Annotations already establish readOnly, idempotent, non-destructive, closed-world behavior, so the description's value-add here is provenance and failure modes: 'served from the record as read; nothing new is collected and nothing is inferred', plus a concrete enumeration of typed errors (unknown_issuer, ambiguous, not_on_record, invalid_request). That is genuinely useful context beyond the structured fields. It omits result-size limits or pagination behavior, which keeps it from a 5.

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?

The purpose is front-loaded in the first clause, which is good, but the single sentence is heavily run-on and laced with jargon ('signed by the node of the issuer's market and receipted') that consumes space without informing tool selection. The error list and 'door' URL are useful but would read better as separate, shorter statements.

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 burden of describing returns, and it does list the record fields delivered per filing. The typed error taxonomy further covers failure behavior, which is unusual and helpful. What is missing is any sense of volume (how many filings, any caps) for a date-range query that could span years.

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 all four parameters are already documented in the schema, establishing a baseline of 3. The description restates the issuer identifier forms (ticker, ISIN, LEI) already present in the schema and adds only the vague 'signed by the node of the issuer's market' framing for the market parameter rather than clarifying its semantics.

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+resource ('disclosures of an issuer in a date range') and enumerates the returned fields (type, date, source page, read date), so the agent knows exactly what it retrieves. It stops short of distinguishing itself from siblings like resolve_issuer, which matters because the 'ambiguous'/'unknown_issuer' errors imply a resolution step is often needed first.

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?

Usage is only implied: the reader infers this is the endpoint for pulling an issuer's filings once a date range is known. There is no explicit when-to-use versus resolve_issuer, and no guidance on handling the 'ambiguous' error the description itself raises. The 'nothing new is collected' clause hints at read-only lookup scope but is not routing guidance.

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