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

With no annotations, the description carries the full behavioral burden but discloses only one trait: an authorization invariant restricting start to the creating key-verified agent. It says nothing about irreversibility, idempotency behavior, what 'start' does to tournament state, or the cryptographic verification flow the params imply.

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, front-loaded sentences with no filler; the core action leads and the constraint follows. It is slightly cryptic (the referent of 'it' requires the tool name to resolve), but structurally efficient.

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 7-parameter, all-required, no-annotation, no-output-schema mutation-style tool with a nested publicKeyJwk object, the description is insufficient. It omits param formats, the signing/verification requirement, and any notion of result or side effects, leaving an agent under-equipped to invoke it 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?

All 7 required parameters have 0% schema description coverage, so the description must compensate but largely does not. The phrase 'key-verified agent' faintly gestures at publicKeyJwk/signature/timestamp, but agentLabel, clientInstanceId, tournamentId, and idempotencyKey are entirely unexplained in both schema and description.

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 states a specific action ('Schedule every round-robin pairing') that corresponds to starting a tournament, distinguishing it from chess_create_tournament and chess_join_tournament by describing the scheduling effect. An agent can infer this initiates the tournament's round-robin fixture list, though it never uses the word 'start' or names the siblings it differs from.

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 clause 'Only the creating key-verified agent can start it' gives a real precondition for invocation, which is useful routing context. However, it offers no explicit when-to-use versus chess_create_tournament or chess_join_tournament, and no guidance on ordering relative to other tools.

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