Is this agent's spending behaving normally? A named z-score test and the counterparty that drove it (PAID $0.05)

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

The description adds genuinely useful context the annotations do not cover: the call costs $0.05, is paid via x402/USDC on eip155:8453, and is invoked as POST /v1/spend/anomaly. That is valuable for an agent that must authorize payment. It does not, however, explain what happens when baseline is omitted, whether results are cached, or what triggers readOnlyHint=false, leaving the mutation-vs-compute nature ambiguous.

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?

It is short and front-loaded, so nothing is bloated, but the first sentence is a verbatim restatement of the title and the only substantive content (price, route, payment rail) is tacked on at the end. The valuable information is buried under a duplicated tagline.

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 output schema lets the description skip return values, and the cost/route disclosure is helpful, but for a nested-object tool at 33% schema coverage the description says nothing about required vs optional inputs or the meaning of the baseline. An agent cannot assemble a correct call from this definition alone.

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 33% and the description contributes zero parameter meaning — agent_id, spend_window, and every sub-field of baseline (observations, std_per_hour, window_hours, mean_per_hour) are undocumented in prose. With a nested object schema and optional baseline, the agent cannot tell whether the baseline is computed from the window or must be supplied.

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 appears to say what the tool does — run a z-score test against a spend baseline and return the counterparty that drove the anomaly — but it is phrased as a marketing question rather than a verb+resource statement. It never differentiates itself from close siblings such as v1_spend_ledger_attest, v1_agent_treasury_report, or v1_budget_preflight, so an agent must infer the boundary.

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?

No when-to-use, when-not-to-use, or alternative routing is given. With ~130 siblings including several spend/treasury tools, the absence of any selection guidance is a real gap; the only conditional information is the price and route.

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