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

Annotations already indicate readOnlyHint=true and destructiveHint=false, and the description adds non-annotated behavioral detail: the data is a weekly Friday-close snapshot, mirrors a particular public URL, and contains only free-tier information. It also clarifies that full composition and P&L are not included, helping the agent set expectations.

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 description is well-structured and front-loaded with the core subject, followed by the returned fields and scope boundaries. It contains no filler, though the enumerated book list partly duplicates the schema and makes the first sentence slightly longer than necessary.

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?

Given only one optional parameter and no output schema, the description is sufficiently complete: it states the source, update frequency, output fields, and the public/subscriber boundary. An agent can accurately decide whether this tool fits a request and what to expect in the result.

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 parameter's meaning is fully documented in the input schema. The description repeats the book list with human-readable names and implies omit-for-all behavior, but it does not meaningfully extend the semantic information already present in 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 clearly identifies the tool as retrieving Closelook's live reference portfolios (public snapshot) and specifies exactly what data is returned: snapshot date, position count, top-10 holdings, and headline return vs deposited capital. The list of included books and the distinction from subscriber-only content makes the purpose actionable and distinct from the sibling tools.

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 clear context for when to use this tool: to retrieve the public portfolio snapshot, exactly as shown on the free page and on closelook.net/portfolios/. It also clarifies what is excluded (subscriber-only composition, cost basis, P&L), though it does not explicitly name alternatives or contrast with sibling tools.

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