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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description goes beyond them with genuinely useful operational context: cost (0.005 credits per call) and an unauthenticated access tier capped at 25 calls/day per address. It does not describe the shape of the portfolio data returned, which is the main remaining gap.

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?

A single sentence with the core purpose front-loaded and the endpoint, price, and quota details relegated to a parenthetical. Nothing is redundant, though the parenthetical is dense enough to slow scanning slightly.

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 read-only endpoint with no output schema and 0% parameter coverage, the description should clarify the return payload and the meaning of as_of. It covers pricing, auth, and quota well, but leaves an agent guessing about response contents and one of the two parameters.

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 0%, so the description carries the burden and only partially meets it. The URL template reveals that 'slug' is a path identifier, but the 'as_of' date parameter is never mentioned, and neither parameter's format or semantics (e.g. which quarter, how as_of interacts with the snapshot) is explained.

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-ish resource: 'One guru's full portfolio at a quarter', which tells an agent it retrieves a single guru's holdings snapshot. It is distinguishable from guru_moves (changes) and gurus (listing), though it never explicitly names those siblings to sharpen the contrast. 'At a quarter' is mildly cryptic but interpretable as a quarterly snapshot.

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?

The description gives no when-to-use guidance and does not mention alternatives like guru_moves or smart_money_holdings. The only conditional information is quota-related ('works with no credentials up to 25 call(s)/day per address'), which is rate-limit info rather than selection guidance.

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