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

Annotations already flag a non-read-only, open-world call, and the description adds the commercial behavior ($4.99 plus tax, one-time, no subscription) plus the crucial agent-conduct rule not to pay on the user's behalf. It leaves out whether repeat calls create duplicate Stripe links or expire.

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 action, with pricing and input hints packed in without filler. The middle pricing clause is slightly dense but each sentence carries usable 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?

With no output schema, the description implies a link is returned but does not describe the return shape or failure modes (invalid code, already-unlocked calendar). For a two-parameter open-world payment tool, that leaves a meaningful gap.

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?

Schema coverage is already 100%, but the description adds real interpretation: 'code' is the ?c= portion of the invite link, clarifying how to extract it from a pasted URL. That meaning is not in the schema's 'invite code or admin code' text.

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 and resource ('Get a Stripe payment link that unlocks a Junto calendar') and immediately scopes what the link does (unlimited members, AI assistant access). It is clearly distinct from the unrelated siblings about_junto and create_calendar.

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?

Gives clear context for use ('The user opens the link and pays; never pay for them') and states the required inputs. It does not cover the when-not case, e.g. what to do if the calendar is already unlocked or if the user lacks admin rights.

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