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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context beyond them: no external HTTP calls and deterministic results given backend state, which tells the agent the call is cheap and stable to repeat. It does not cover item shape, but the output schema handles that.

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?

Front-loaded with the return value, then side effects, then usage, all in a compact block. The 'read-only' note mildly duplicates the readOnlyHint annotation, costing a little redundancy, but the rest of the sentence earns its place.

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 no-arg list tool with a full annotation set and an output schema, the description supplies everything needed: what it returns, where it reads from, determinism, and how the result feeds other tools. Return-value detail is correctly left to the 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?

The tool takes zero parameters, so the baseline is 4. The description still helpfully explains the role of the value it produces (profile names, consumed as profile_name elsewhere) without inventing parameter semantics that don't exist.

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?

States a specific verb and resource ('Return all distribution profile names') and scopes it to the 'YAML backend', which clarifies it is not scanning external systems. An agent can distinguish it from the post_* siblings, which perform actions rather than enumerate profiles.

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 tells the agent when to use it ('to discover available profiles before calling post_publish, post_schedule, or subreddit_list') and what to do with the result ('pass the chosen name as profile_name'). This is a full when-to-use plus downstream wiring, leaving nothing to inference.

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