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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), and the description adds a genuine behavioral fact beyond them: the action is effectively one-way because unblocking happens in the app, not through MCP. It does not cover idempotency or what happens to existing message history, which keeps it from 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 short sentences, front-loaded with the effect and followed by the unblock routing note; nothing is filler. The phrase 'in the app' is slightly vague about which surface, but the structure is 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 single-parameter mutation with annotations and no output schema, the description supplies enough to invoke it correctly, and the unblock note covers the main follow-up question. Success/failure behavior and any permission requirements are left implicit.

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% and the single otherUserId parameter is documented there as the student's user id, so the schema carries the burden. The description adds no format, lookup, or constraint detail beyond that.

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 definition uses a concrete verb and resource combination ('stops a person from sending messages to the trainer') and states the direction of the block, which differentiates it from read-only siblings like get_chat_block_status. It stops short of naming that sibling explicitly, so the boundary must be inferred.

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 'Unblocking is in the app' usefully implies there is no complementary API tool, but there is no explicit when-to-use guidance, no mention of get_chat_block_status for checking current state, and no stated preconditions such as whether the target must already be a student.

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