Add To Watchlist

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

Annotations already declare the tool as non-read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds the 'user's watchlist' scope, which is useful context, but it does not disclose behavior such as what happens if the symbol already exists or whether the data_source must match an existing platform. This is acceptable given the annotations.

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 a single, efficient sentence with no filler. The core action and target are front-loaded, making it immediately scannable for an agent. Nothing extraneous is included.

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 simple two-parameter mutation tool, the description, combined with the schema, annotations, and presence of an output schema, provides enough context for correct invocation. The annotations cover idempotency and non-destructiveness, the schema fully documents parameters, and the output schema handles return-value expectations, so no critical information is missing.

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 input schema already documents both parameters with clear descriptions and 100% coverage. The tool description adds no additional parameter-level meaning beyond the schema, so the baseline of 3 is appropriate. It does not clarify allowed values for data_source or any relationship between symbol and data_source, but the schema provides adequate guidance.

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 states a specific verb ('Add'), a specific resource ('symbol'), and the target context ('user's watchlist'). This clearly distinguishes it from sibling tools like get_watchlist and remove_from_watchlist, so an agent can identify the correct operation without ambiguity.

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 implies the use case: use this when the user wants to add a symbol to their watchlist. However, it does not explicitly mention alternatives or when not to use it, such as using remove_from_watchlist for removal or get_watchlist for viewing. Usage context is clear but not explicitly differentiated.

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