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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely useful context beyond that: the check is bidirectional (blocked by trainer or blocked by the other person), which an agent wouldn't know from the schema alone.

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?

A single short sentence with no filler, and the key scope point (both directions of blocking) is front-loaded. It is arguably slightly too terse rather than padded.

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?

This is a simple closed-world read with complete schema coverage and clear safety annotations, so little is needed. However, the description doesn't indicate the shape of the answer (boolean, status object, which direction is blocked), which matters for a status-query tool with no output schema.

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 single otherUserId parameter (student_id) is fully documented in the schema. The description adds nothing about the parameter, so the baseline of 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?

The description identifies the resource (chat block status) and the bidirectional nature of the check, but it's phrased as a sentence fragment with an implied verb and never says what the tool returns. It also doesn't distinguish itself from the sibling block_chat_user, which an agent could easily confuse with it.

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?

There is no guidance on when to call this versus alternatives such as block_chat_user (the mutation) or read_chat. The agent must infer that this is the pre-check read counterpart to blocking.

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