get_fund_nav

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

The annotations already cover the read-only and open-world profile. The description adds genuine behavioral context beyond them: the tool auto-routes to the correct CVM dataset, and it discloses that FIF/FAPI data is daily while FII/FIDC/FIAGRO data is monthly, which materially affects interpretation. It stops short of mentioning row truncation or pagination behavior around max_rows.

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 leading sentence front-loads the purpose and the mechanism, and the bullet list is compact and scannable per dataset type. Every line conveys distinct information; no filler. Slightly more markup than strictly necessary, but it aids scanning.

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 the description need not explain return values, and annotations carry the safety profile. What remains is a simple read-only lookup with four documented parameters, which the definition covers adequately. Minor gap: no note on how fund name matching or date-range defaults interact.

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 schema already documents fund, max_rows, first_period and last_period. The description adds no syntax or format guidance for these parameters. The dataset bullets give indirect signal about which period granularity to expect, which is why this sits at the baseline rather than a 2.

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 states a specific verb and resource: 'NAV time series for any fund', and adds the key mechanism, routing to the correct CVM dataset. The per-dataset bullet list makes the returned content concrete for each fund type. It does not explicitly distinguish itself from the closest siblings (get_fund_flows, get_fund_portfolio), which keeps it short of a 5.

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 implied by the enumeration of supported dataset types (FIF/FAPI, FII, FIDC, FIAGRO), so an agent can infer it applies to any fund. There is no explicit when-to-use versus get_fund_flows or get_fund_portfolio, and no stated prerequisites or exclusions. Adequate but leaves the sibling routing to inference.

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