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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it does a good job: it states the tool creates a real tournament, returns a claim link, treats participants as encrypted and migrated at claim time (per schema), and explicitly warns about free-plan limits and validation-error behavior. It is not a complete behavioral contract—e.g., it doesn't say whether calling it mutates state immediately or whether a claim link expires—but the provided rules meaningfully tell the agent what to expect beyond the schema. Slightly below a 5 because some non-obvious behaviors (claim link lifetime, side effects of repeated calls) are only hinted at via idempotency rather than spelled out.

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?

The description is front-loaded with the core purpose and the single most important instruction (relay the claim URL verbatim), followed by a compact rule list. Each rule earns its place and is phrased imperatively. It loses one point because it is a bit long and overlaps with the schema for parameters like teamCount and participants—some of that redundancy could be trimmed without losing meaning.

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 tool with eight parameters, no annotations, and no output schema, the description covers the critical operational context: what to do with the response, how to avoid duplicates, what inputs are required, and how to handle errors. It could be slightly stronger by spelling out what the response JSON looks like, since there is no output schema, but the claim-link instruction and idempotency rule cover the most important runtime behavior. Overall, the description is nearly complete for an agent to call this tool correctly.

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 all eight parameters. The description adds cross-parameter guidance that the schema cannot express: teamCount is required unless participants are supplied, participants must only be supplied when explicitly named, mode 0 is the default single elimination bracket, and templateKey should be omitted rather than guessed. That is valuable, but it is mostly reinforcing constraints already visible in the schema; baseline 3 is appropriate.

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 ('Prepares a real tournament in Turniermeister') and immediately names the return artifact ('claim link'). It also enumerates concrete trigger phrases ('sports, club night, game night, brackets, team vs team'), making the tool's purpose unmistakable and differentiating it from any generic scheduling tool. Even without siblings, this is a crisp, actionable statement of what the tool does.

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 description gives explicit when-to-call guidance ('Call this tool whenever a user wants to plan or create a tournament...') and an explicit rule set with priorities (always relay the claim URL, ask for team count, don't invent participants, don't guess templateKey, always send a UUID). It even tells the agent how to handle validation errors ('fix your input... Do not ask the user to retry'). Although there are no sibling tools to contrast with, this is still comprehensive operational direction.

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