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

Beyond the readOnly/idempotent/non-destructive annotations, the description discloses publication lag, default-to-latest behavior, and the exact failure modes (found:false with close names, ambiguous-name candidate list). It also identifies the upstream source, which helps the agent judge data freshness and authority.

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 content is dense and front-loaded: the resource and metrics come first, then fund selection, then time modes, then error behavior and source. It is somewhat long as a single block, but nearly every clause carries operational value.

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 an output schema present and annotations covering safety, the description fills the remaining gaps an agent needs: how to identify the fund, absence of required parameters, default date behavior, range limits implied by help text, and error handling. Nothing material for correct invocation appears missing.

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 coverage is 100%, so the baseline is 3, but the description adds meaning beyond the schema: the fund name match is forgiving, fund_code is exact and skips name matching, and the date/from/to modes are mutually contextualized. The limit parameter's role is left to the schema.

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 resource (Colombian FIC unit value and returns), the exact metrics returned (daily/monthly/semester/annual profitability, fund size, investor count), and the per-participation-class granularity. It also distinguishes itself from co_fic_search by positioning that sibling as the source of fund codes.

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 explains how to select the fund (forgiving name match or fund_code from co_fic_search) and how to choose the time mode (default latest, date for one day, from/to for history). Unknown and ambiguous name outcomes are also addressed, though there is no explicit guidance on when not to use this tool versus deeper research alternatives.

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