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

Annotations only mark it non-read-only, open-world, non-idempotent and non-destructive; the description goes much further by disclosing that it schedules REAL posts across multiple days, the posting cadence (one per variant per round), and the side effect that list_hook_rules/check_draft stay empty until the test concludes. That is precisely the context a mutation tool needs.

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 sentences, front-loaded with the action, then the critical warning in caps, then the downstream consequence. Every clause carries information and nothing is padding.

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 an 8-param scheduling mutation with no output schema, the description covers the action, the side effects, the human-in-the-loop requirement, and where results surface. Combined with the fully documented schema, an agent has everything needed to call it correctly.

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%, so the schema already documents all 8 parameters in detail, including the archetype-to-opening-matching rules. The description adds only the high-level shape ('several openings for the same idea') without new syntax or constraint detail, so the baseline 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?

States a specific verb (start a hook test) plus the mechanism (publish several openings for the same idea, measure which holds attention) and names the downstream consumers (list_hook_rules, check_draft). Clearly separable from siblings like schedule_post or list_posts.

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 requires human confirmation before calling ('confirm with the person before calling it') and explains that results only materialize after the test concludes. It does not, however, name the alternative tool (schedule_post) for the case where a single ordinary post is wanted, so routing vs. that sibling is left to inference.

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