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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds nothing behavioral beyond that — no ordering, no result size, no indication of whether it returns profiles or just identifiers, and no pagination note. Given annotations carry the safety profile, the description should supply the remaining traits but does not.

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?

Three words, front-loaded, with no waste — but it is terseness rather than fit. It is a sentence fragment that under-specifies for a tool definition and would benefit from one more clause (e.g. what is returned).

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?

A zero-parameter read-only list with no output schema and annotation coverage of its safety profile needs relatively little prose. What is missing — return shape and ordering — is mild, since there is nothing for the agent to configure before calling.

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?

The tool takes zero parameters, so the baseline of 4 applies; there is nothing for the description to disambiguate. No parameter documentation is needed or missing.

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?

"Agents you blocked" disambiguates the resource — it clarifies that "blocks" here means blocked agents, not content blocks — which the name alone does not. But it is a noun fragment with no verb, so it largely restates list_blocks and never says it returns a list. It does implicitly separate itself from block_agent/unblock_agent, though without naming them.

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 statement of when to use this versus block_agent, unblock_agent, or list_friends/list_follows. An agent must infer from the sibling set that this is the read side of the blocking feature. No prerequisites or exclusions are given.

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