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

The annotations already state readOnlyHint=true and openWorldHint=false, so the safety profile needs no repeat. The description adds genuine context beyond them in the form of cost and billing requirements (5 prepaid credits, production billing required). It leaves out the decision behavior entirely, though: whether the tool returns a pass/fail verdict, how it weighs error versus latency, and what a non-production environment does.

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 with the core comparison stated first and the billing gate second, and no padding. It is tight, though the extreme brevity is part of why parameter and behavior details are missing.

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?

This is a read-only guard tool with 5 undocumented required parameters and no output schema. The description says what is compared but not how the comparison resolves into a verdict or what the agent should do with the result, so the definition is not complete enough for confident invocation.

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 5 required parameters, so the description must carry the full explanatory burden, and it names none of them. The parameter names (baseline_error_pct, canary_error_pct, baseline_p95_ms, canary_p95_ms, max_error_delta_pct) are largely self-describing, which helps. But the critical semantics are absent, especially how max_error_delta_pct gates the comparison and whether any latency threshold 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 verb and resource: comparing error and latency metrics between canary and baseline. That is much clearer than the title alone. However, it does not distinguish itself from related siblings such as privi_pro_error_budget, privi_pro_latency_slo, or privi_pro_circuit_threshold, so an agent cannot easily tell which threshold-style tool to select.

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 purpose implies when the tool is useful: validating a canary release before promotion. The description also gives one real prerequisite: paid-only access with 5 prepaid credits and production billing required. It never says when not to use it, however, nor points to any alternative for simpler threshold checks.

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