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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false). With no output schema, the description usefully discloses the return shape: exactly 8 lines, each tagged with one of six named hook types plus the underlying psychology. It omits cost/latency behavior, keeping it from a 5.

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 dense sentence that front-loads the deliverable (8 opening lines) and packs the labelling scheme in a parenthetical. Every clause earns its place; nothing is redundant.

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 two-parameter generator with no output schema, the definition covers the deliverable, its structure, and the labelled hook taxonomy. Safety is handled by annotations and params by the schema. Only minor gaps (no mention of platform's effect on output, no cost/limits) remain.

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 both the required product input and the platform enum are fully documented in the schema. The description adds no syntax or format detail beyond that, 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 (Write) and a precisely quantified resource (8 scroll-stopping opening lines for a UGC-style video ad), including the labelling scheme. This is enough for an agent to distinguish it from write_ugc_script (full script) without opening either schema.

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?

The description implies the usage context (creating ad hooks) but never says when to reach for this tool versus siblings like write_ugc_script or rewrite_ad_for_product, and offers no exclusions or prerequisites. Usage is inferred rather than stated.

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