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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description goes further by disclosing exactly what the payload contains (tickets, receipts, refunds, line items, billing address, payment details), which is meaningful behavioral context beyond the annotations. It does not cover auth scope or rate limits, so it is not 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 tightly packed sentences, front-loaded with the action and resource, and the trailing API endpoint reference is a compact aid for mapping to Tito docs. No filler.

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 compensates by enumerating the major returned sections, which is enough for an agent to know what it gets back. It omits pagination/expansion options and error behavior, but for a single read-only fetch it is largely complete.

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 description coverage is 100%, so the schema already documents event_slug, account_slug (including the TITO_ACCOUNT fallback) and registration_slug. The description restates the registration slug format but adds nothing new about the parameters, 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?

States a specific verb and resource ('Fetch a single registration (order) by slug') and clarifies the identifier format (reg_...), which implicitly contrasts with the list sibling tito_list_registrations. It stops short of naming that sibling explicitly, which is the only thing keeping it from a 5.

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?

The single-record-by-slug framing implies when to use it versus a list call, but there is no explicit statement of when to prefer this tool, no prerequisites, and no named alternative. Usage is inferable but not spelled out.

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