KARTA — spend control for AI agents

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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses that 'No state is stored' and lists returned fields, but it does not explain permissions, idempotency, rate limits, or whether the check has side effects beyond the stated no-state behavior.

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 sentences, front-loaded with the core operation and followed by return fields and state behavior. There is no wasted language, and the most important scoping information comes first.

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?

The tool has six input parameters, a nested object, no parameter descriptions, and no annotations. Although an output schema exists and the description need not fully explain return values, the input-side description is far too sparse to compensate for the schema coverage gap.

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?

Schema description coverage is 0% across six parameters, including a nested `envelope` object and optional counters like `calls_so_far` and `spent_so_far`. The description only indirectly hints at envelope/amount/payee and adds no format, unit, or semantic detail for the undocumented parameters.

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 and resource: 'Check whether a proposed agent spend is inside a task envelope.' It clearly scopes the operation to spend validation against a task envelope, so an agent can understand the tool's purpose without opening the schema.

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?

Usage is implied by the phrase 'proposed agent spend' and 'task envelope,' which indicates this is a pre-authorization check. However, there are no explicit when-to-use, when-not-to-use, or alternative-tool instructions, and no siblings are provided to differentiate against.

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