Axcel plans

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is fully covered structurally. 'This MCP never buys anything' adds a small amount of context about absence of purchase side effects, but largely restates the read-only hint without describing the returned price shape or freshness.

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 no filler, and the scope statement ('read-only list of plans and prices') is front-loaded ahead of the caveat. Every sentence earns its place.

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 listing tool with no output schema, saying it returns plans and prices is close to sufficient, and the safety annotations cover the rest. It stops short of describing what a plan record contains or whether results are cached, which would fully close the loop.

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-carries-nothing baseline of 4 applies. The description correctly adds no parameter claims, and there are no undocumented inputs to compensate for.

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 states a specific verb (list) and resource (Axcel plans and prices), so an agent immediately knows what it returns. It does not name or contrast against any sibling, but none of the surrounding tools are billing-related, so the risk of confusion is low.

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?

'Read-only list of Axcel plans and prices' implies the usage context (checking pricing), but there is no explicit when-to-use or when-not-to-use guidance and no named alternative. The closing sentence hints at scope limits but is framed as a behavioral claim rather than a usage rule.

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