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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds behaviorally relevant context beyond annotations: returns current data, requires no authentication, and clarifies that one metered allowance spans REST and MCP usage.

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 sentences, front-loaded with the core resource and then expanding on specifics. No filler, no repetition of annotations, and every sentence adds distinct useful 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?

For a zero-parameter read-only tool, the description sufficiently explains what output to expect (tiers, monthly price, included allowance, overage rates) and relevant usage constraints (no auth, metered allowance spanning REST and MCP). No output schema exists, but the description covers the essential return values and behavior.

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 schema description coverage is 100%, so there are no parameter semantics to explain. The no-parameter baseline of 4 applies; the description doesn't need to add parameter details.

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 returns current developer-platform plans and pricing, listing the specific tiers and cost details. The resource 'plans and pricing' is distinct from sibling tools get_documentation and sign_up, making it easy for an agent to differentiate without needing to open those definitions.

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 provides useful context—current plans, no auth required—but does not explicitly state when to use this tool versus get_documentation or sign_up. No exclusions or alternative routing is given; the usage is implied by the specific subject matter rather than explicitly directed.

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