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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description goes beyond that by disclosing the fields the response will carry, which matters here because there is no output schema. It does not mention auth needs, rate limits or error behavior, so it falls short of a 5.

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, front-loaded with the resource and its returned fields. The trailing 'GET /locations/{location_uuid}/plan' is mildly redundant with the tool name and schema path, but the text is otherwise free of padding.

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 single-parameter read with annotations covering safety and no output schema, the definition is nearly sufficient — the response contents are spelled out in the description. It lacks only guidance on when this call is warranted versus other location lookups.

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?

There is one parameter and schema coverage is 100%; the schema description already explains it is a Homebase location uuid sourced from homebase_list_locations. The description adds nothing about the parameter beyond repeating the path variable, so the baseline 3 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?

Names a specific verb and resource ('The Homebase subscription plan of a location') and enumerates exactly what the plan object contains: plan number, price, last update and trial state. No sibling tool retrieves a plan, so it is unambiguously distinguishable from the other homebase_get_* tools.

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 resource name — call it to read a location's plan — but there is no explicit when/when-not statement or named alternative. The only routing hint ('from homebase_list_locations') lives in the schema, not the description.

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