List Watchlist sources

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds useful behavioral nuance: the response conditionally includes stored token PnL cost-basis rows when the API has them, and the operation never mutates data. This complements the annotations without contradicting them.

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?

Two crisp sentences lead with the primary action, then add a conditional inclusion detail, then close with a scope boundary. There is no filler and every sentence contributes information an agent needs to invoke the tool correctly.

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 zero-parameter, read-only listing tool with an output schema available, the description covers what is listed, the conditional PnL inclusion, and the non-mutating nature. Nothing essential is missing for an agent to decide on and execute this tool correctly.

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?

The tool accepts no parameters, so the input schema is already complete. Per the baseline for zero-parameter tools, there is nothing further the description needs to compensate for, and it introduces no parameter-related ambiguity.

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 uses a specific verb ('List') and a defined resource ('Watchlist wallets, exchanges, and manual bank/cash/property sources'), which immediately clarifies what is returned. The boundary clause 'Does not add wallets or edit assets' distinguishes the tool from mutation-focused siblings like create_invoice. This makes the tool's scope unmistakable.

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 clearly establishes when to use the tool: to retrieve a read-only list of watchlist sources, including PnL cost-basis rows when available. It also states a when-not boundary: it does not add wallets or edit assets. However, it never names sibling alternatives such as get_source for a single source, so it stops short of full 5 guidance.

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