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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds substantive context beyond that: it discloses the exact categories of data returned (USD/INR pricing, site limits, credits, trial state) and that pricing_url is where purchase occurs, which tells the agent this is a read-only informational snapshot with no side effects.

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?

One dense sentence that front-loads the core purpose (plans + caller entitlement) before the payload enumeration. It is long but every clause adds a distinct data category, and there is no filler or restated title text.

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?

There is no output schema, so the description must carry the return-value burden, and it does so thoroughly: catalogue contents, currency variants, limits, credits, features, entitlement state, and the purchase URL. Combined with annotations covering the safety profile, an agent has everything needed to call and interpret this tool.

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 takes zero parameters, so the schema-baseline of 4 applies; there is nothing for the description to clarify beyond what the empty schema already establishes. The description correctly implies the call is context-scoped to the caller rather than parameterized.

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+resource (retrieves Pylon SEO plans plus the caller's entitlement) and enumerates the concrete payload: paid catalogue tiers, currencies, site limits, credits, features, current plan, usage, trial state, and purchase URL. It is clearly distinguishable from the many analytical siblings like get_site, get_score_history, or get_gsc_metrics.

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?

Usage is implied by the content (call when you need plan/pricing or entitlement context), but there is no explicit when-to-use statement, no prerequisites, and no routing to or away from alternatives. The agent must infer the trigger condition from the resource description alone.

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