Portfolio Overlap Between Institutions

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

Annotations provide readOnlyHint=true, but the description adds substantial behavioral context: it lists the exact overlap metrics returned, notes that prices normally use report-date closing values but may fall back to filer values and can be zero when unavailable. This data-quality caveat is valuable beyond the annotation, though it doesn't cover auth or rate limits.

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 efficiently front-loaded sentences: purpose, return values, data caveat, and alternatives. Each sentence adds useful information, though the data-quality sentence could be slightly tighter without losing meaning.

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 comparison tool with no output schema, the description adequately explains return values, data caveats, and alternative tools. It does not mention the maxResults limit or pagination behavior, but the schema covers maxResults, and no output schema exists to require additional explanation.

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 all four parameters thoroughly. The description adds the name-resolution tip and clarifies the 'common report date' concept, which gives some extra meaning, but the baseline of 3 is appropriate since the schema carries the primary documentation burden.

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 (Compare), resource (institutions' 13F portfolios), and scope (latest common report date). It also names the return contents and differentiates from sibling tools like GetFundProfile and SearchInstitutions. An agent can immediately tell what this tool does.

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?

Explicitly names alternatives for specific cases: 'Resolve filer names with SearchInstitutions' and 'For mutual-fund or ETF NPORT portfolios, use GetFundProfile.' These are clear when-to-use and when-not-to-use directives that prevent mis-invocation.

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