Overview — Request budget

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

Goes well beyond the readOnlyHint/destructiveHint annotations by disclosing that the tool costs no API requests, that the quota belongs to the access token and is shared with the user's own YNAB apps, and that the reported figure reflects this server's spend rather than YNAB's true remainder.

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?

Four sentences, each earning its place, with the direct answer ('how many requests remain') front-loaded before the caveats about scope and cost.

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?

An output schema exists so return values needn't be described; the description supplies the quota semantics, the approximate limit, and the zero-cost trait that an agent needs to use the result 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?

There are zero parameters, so the schema carries no semantic burden and the description has nothing to add; baseline 4 applies.

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 verb (read) and resource (remaining API request budget in the current rolling hour) and distinguishes itself from every sibling by noting they already return requests_used_this_hour and requests_remaining.

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?

Explicitly scopes when to call it: 'call this one only for the rest: the limit, the window, and when an exhausted budget reopens', and tells the agent not to call it for data already present in other tools' responses.

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