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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable context: 'Free — no credits charged' clarifies cost implications, and 'today's' scopes the operation. It does not contradict 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?

Two short sentences deliver all core information without filler. The first sentence leads with the primary action and output, and the second adds cost context. Every word earns its place.

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 is simple (1 optional param, output schema exists), and the description covers its purpose and scope. However, it does not clarify why one would choose this over the closely related burnrate_track, leaving a minor completeness 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 100% for the single optional daily_limit parameter, which fully explains the parameter's meaning. The description itself does not add parameter details, but the schema carries the burden, so baseline 3 is appropriate.

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 states the tool retrieves today's tracked LLM spend, per-model breakdown, projection, and budget alerts. The verb 'get' plus the resource (budget info) is specific and differentiates it from siblings like burnrate_track or burnrate_estimate.

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 usage by mentioning budget alerts and spend tracking, but it does not explicitly state when to use this tool versus alternatives like burnrate_track or burnrate_optimize. No exclusion criteria or alternative references are provided.

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