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

Annotations already declare destructiveHint=false and openWorldHint=false, so the safety profile is largely covered. The description usefully adds that output is exactly three lines drawn from distinct angles, but it says nothing about voice/profile usage, determinism, or rate behavior for a generation tool.

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 tight sentences with zero filler, and the core output definition is front-loaded ahead of the usage trigger. Every clause 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?

With no output schema, the description carries the burden of describing returns and does so (three hooks, five possible angles). It is nearly complete, though it omits whether the user's voice profile influences generation, which is implied by sibling tools like get_voice_profile.

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 'topic' (1-240 chars) and the 'platform' enum with its omit-to-inherit semantics are already fully documented. The description adds no parameter-level detail beyond the schema, so 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?

Specific verb ('Generate') plus resource ('opening lines/hooks') with an exact output count (3) and enumerated angles (contrarian, story, listicle, reframe, observation). This distinguishes it from the nearby get_post_ideas and improve_post siblings, which operate on full posts rather than first lines.

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 states when to use it: 'when the user asks for a hook, a first line, or doesn't know how to start.' That is clear routing context, but it names no alternatives or when-not conditions (e.g., versus get_post_ideas), so it stops short of a 5.

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