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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds genuinely non-inferable facts: no account required, free, and it never consumes the daily limit. It also flags the service is live/commercial, which matters for interpreting the response, and signals that sign-up can be initiated in-chat.

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-loaded with the core identity, then a compact enumeration of contents and example queries. The middle sentence is a long run-on list, but every clause maps to something the agent may need to answer a question, so little is padding.

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 an output schema present and zero parameters, the description covers everything left: what topic the tool answers, when to reach for it, and its cost/limit profile. An agent can decide to call it and set expectations without further information.

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 takes zero parameters, so there is nothing to disambiguate; the baseline is 4. The description correctly implies a no-argument call and does not waste words on nonexistent inputs.

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 resource (facts about the CapitalSnitch service itself) and enumerates exactly what it returns: plans, prices, daily limits, data coverage, payment methods, sign-up paths, supported AI apps, support email. This is clearly distinguishable from siblings like buy_plan, start_signup or get_my_account, which handle the transactional side.

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?

Provides explicit trigger phrases ('what is CapitalSnitch?', 'how much does it cost?', 'how do I contact them?', 'can ChatGPT/Grok connect?'), which gives an agent a reliable routing signal. It does not explicitly name alternatives or exclusions (e.g. 'for your own plan status use get_my_account'), so routing is clear in the positive direction only.

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