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

Beyond the annotations, the description discloses important behavior: the call is free and does not count toward the daily question limit, and authentication is via the personal connection address with no email or password required. These are exactly the operational details an agent needs and annotations do not provide.

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 front-loaded with the account contents, then usage examples, then authentication context, and it is reasonably efficient. Some field enumeration overlaps with what the output schema likely provides, and a few clauses could be tightened, but it is not bloated.

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 zero parameters, an output schema, and safe read-only annotations, the description is complete: it explains what the account object covers, when to call it, that it is free, and how the user is identified. An agent has everything needed to select and invoke it 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 takes zero parameters, so the baseline is 4. The description adds relevant context that no email/password is needed because the user is inferred from the connection, but there are no parameters whose semantics require further explanation.

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 resource as the user's own CapitalSnitch account and enumerates the concrete account/subscription information it exposes: plan, status, renewal/expiry dates, payment method, quota usage, and feature access. The phrase 'user's own' distinguishes it from account-adjacent siblings such as about_capitalsnitch and buy_plan 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?

It gives concrete trigger phrases ('what plan am I on?', 'when does my subscription renew?', 'is my plan active?', 'how many questions do I have left?'), which is strong usage context. It does not explicitly state when not to use it or name alternatives like get_account_link or buy_plan, so it falls short of a full 5 under the rubric.

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