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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds meaningful context beyond annotations: quota impact ('counts against the plan's request quota'), auth requirement ('Requires an API key'), error behavior ('Errors if the UUID does not match a profile'), and return shape ('Returns the follow relationship and follower count'). No contradiction with annotations.

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?

Four tight sentences, front-loaded with the core purpose, then usage guidance, then behavioral details. Zero fluff — every sentence contributes (purpose, when-to-use, read-only/quota, return/error). Well-structured for quick scanning.

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 simple single-parameter read tool with strong annotations (readOnly, idempotent, non-destructive), 100% schema coverage, and no output schema needed, the description is complete: purpose, usage context, auth/quota costs, return shape, and error behavior are all covered. Nothing material is missing.

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 coverage is 100% and the schema already thoroughly documents user_id ('UUID of the profile to check, as returned in author fields by article tools. Not the username.'). The description slightly reinforces single-profile semantics ('answers about ONE profile identified by UUID') but adds no new syntax or format details beyond what the schema provides. 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?

Description leads with a specific verb+resource: 'Check whether the authenticated account follows a given profile, and how many followers that profile has.' It clearly states the scope (ONE profile by UUID), and there is no competing follow-status tool among the 23 siblings, so it distinguishes itself by being the sole profile-follow-status query tool.

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?

Explicitly instructs when to use it: 'Use it before offering to follow someone, so you do not suggest an action that is already done.' It also provides a notable exclusion: 'there is no tool here that lists everyone you follow,' which prevents the agent from searching for a nonexistent list capability.

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