spend_report

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

No annotations are provided, so the description carries the full burden, and it does useful work: it discloses the data source (run folders on disk), asserts nothing is recorded elsewhere, and guarantees nothing leaves the machine. It omits the read-only nature, cost units, and behavior on missing/corrupt run folders, keeping it out of the top tier.

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?

Three short sentences, front-loaded with the scope and ending with the action-oriented use case. The privacy clause ("nothing is recorded anywhere else and nothing leaves this machine") is slightly redundant with itself, a minor inefficiency.

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?

For a one-optional-parameter reporting tool this is largely sufficient: scope, data provenance, and intended use are all covered. Because there is no output schema, the description could have sketched what the report returns (per-run breakdown vs. total, units), which is the remaining 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% and the single 'days' parameter is fully documented in the schema (including default and bounds). The description only echoes the window concept ("across a window of days") without adding format or interpretation detail, so the baseline 3 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 resource and scope: the cost of every run across a multi-day window, explicitly contrasting with single-run reporting ("not just one run"). The verb is implicit rather than explicit, and no sibling (e.g. metrics_report, verdict_stats) is named for disambiguation, so it lands just below the top tier.

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?

Gives a concrete triggering scenario: use it to answer "what have I spent today" before starting another run. That is clear when-to-use guidance, but there are no exclusions or named alternatives among the many reporting/run siblings, so it stops short of a 5.

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