Report what this session has spent

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 behavioral context: it is free, fully local, makes no network call, consumes no credits, normalizes figures to US cents, and clearly flags that estimated costs are pessimistic placeholders. This goes beyond the annotations to explain the nature of the data and its reliability, though it does not address any potential concurrency or rate-limit behavior (likely irrelevant for a local read).

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 two sentences with no fluff. The leading 'FREE and fully local: no network call, no credits' is an efficient hook, followed by the core reporting function and the important estimation caveat. Every part adds value, and it is front-loaded with the most decision-relevant information.

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?

Given the tool has no parameters and no output schema, the description fully covers what the agent needs: what is reported (spend breakdown by tool, remaining headroom), the unit normalization, and the caveat about estimated costs. There is no missing detail that would prevent correct invocation or interpretation of results.

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 has zero parameters, and the schema coverage is 100% (empty properties object). Per the baseline rule for 0 parameters, a score of 4 is appropriate. The description does not need to explain parameters since none exist, and it appropriately focuses on the output semantics instead.

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 states a specific verb ('Reports') and a specific resource ('estimated provider spend for this workspace, broken down by tool'), plus the additional output of remaining headroom. It clearly distinguishes from sibling tools, which are all asset-generation/job tools, by being the only spend-related tool. The purpose is unambiguous.

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 does not explicitly state when to use this tool versus alternatives, though no direct alternative exists among siblings. It does convey that it is free and local, implying it can be called without cost concerns, but it lacks an explicit 'use this when you need to check budget' or 'prefer this over external APIs' guidance. The usage context is implied rather than stated.

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