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

Annotations already declare read-only, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely useful context beyond that: it discloses the data source (the fund's SEC filing when one exists) and frames the output as a counterfactual that 'never says whether to buy,' which sets correct expectations for the agent. It stops short of describing cost, latency, or failure behavior for unknown tickers.

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?

Front-loads the capability, then usage guidance, then parameters — efficient and dense with no filler. The opening sentence is a long colon-separated run-on that is slightly harder to parse than it needs to be, but nothing is wasted.

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 annotations covering the safety profile, a full output schema covering return values, and every parameter documented, the description supplies exactly the missing layer: what the tool computes, when to use it versus the sibling, and that it is advisory-only. Nothing an agent needs in order to call it correctly is absent.

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 in detail (including the holdings map format and cash ticker convention). The description's parameter gloss ('add is the ticker considered, amount how much of it in the same units as holdings, base the currency') largely restates the schema rather than adding new semantics. Baseline 3 is appropriate.

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?

Names the specific operation (evaluate one proposed addition against an existing portfolio) and enumerates the three concrete outputs: overlap with current funds, whether it adds an independent bet, and crisis counterfactuals. It explicitly distinguishes itself from the sibling tool, so an agent can route without opening either schema.

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?

Gives an explicit when-to-use ('for one addition') and an explicit when-not with the alternative named ('for removing, reweighting or several changes at once, test_a_change'). The selection condition between the two tools is unambiguous.

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