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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered. The description adds genuinely new behavior: it states the returned content set (plan, trial end date, limits, month-scoped usage) and a conditional branch for the no-plan-yet case, including that a trial-start link is returned. It could go further on what happens outside trial, but this is solid added context.

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, zero filler, with the primary purpose front-loaded and the edge case (no plan yet) placed second. Every clause carries information an agent would otherwise have to guess at.

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?

No output schema exists, so the description must carry the return-value burden – and it does, naming the four data categories returned plus the trial-link fallback. With no parameters and annotations covering the safety profile, there is no meaningful gap left for an agent.

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 no parameters and the schema is empty, so there is nothing for the description to clarify. Baseline for a zero-parameter tool is 4, and nothing in the description introduces confusion about inputs.

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 opens with a specific verb and resource ("Show this workspace's plan") and enumerates exactly what the response covers: plan, trial end date, limits, and monthly usage. None of the sibling tools (all schedule CRUD operations) touch account or plan data, so an agent can route here without ambiguity.

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 only implied by the subject matter – an agent infers 'call this when you need to know the plan or remaining limits.' There is no explicit when-to-use condition, no exclusion, and no alternative named, though for a zero-parameter read tool the risk of mis-invocation is low.

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