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

With no annotations, the description carries the full burden and does substantial work: it discloses that unreported figures return as missing rather than estimated, that restatements are surfaced, that values are in as-filed units, and that values only come from financial statements (10-K/10-Q/20-F/40-F and amendments), never proxies or 8-Ks. It stops short of covering failure modes, latency, or how company identifiers are resolved.

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?

Four sentences, front-loaded with what is returned and the citation payload, followed by the missing-data guarantee, units, and source-document scope. Dense but every sentence adds a distinct constraint; only the final sentence runs long.

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, so return values need not be restated, and the description covers the non-obvious semantics: missing vs. estimated, restatement handling, as-filed units, and eligible filing types. It lacks routing to siblings, which is the main remaining gap for a tool in a crowded financials toolset.

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 and the schema already documents company, concept, period, and as_of formats. The description adds indirect meaning by explaining that restated values are listed and that an as_originally_reported version exists, which contextualizes as_of, but it does not explicitly map that behavior to the parameter.

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 resource ('One reported figure from SEC filings') and enumerates exactly what accompanies it (accession number, form, filing date, XBRL tag, period, link). This implicitly separates it from statement-level siblings like fetch_income_statement and fetch_balance_sheet by scoping to a single cited figure.

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 'one reported figure' framing and the source-document restriction suggest it is for targeted single-metric lookups, but the description never says when to prefer it over fetch_income_statement, financials, or compare_stocks. No explicit 'use X instead' routing is given.

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