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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description adds genuinely useful behavioral context beyond that: 'Costs no credits' and the fact that results are ready to hand to create_character plus a first scene. It does not describe volume/rate behavior, but that is minor.

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-loads the core purpose and covers input, usage, and cost in a compact block with no filler sentences. The parenthetical color ('the paying user, not the prettiest creator') is slightly prose-heavy but still carries meaning, so it is not wasteful.

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 an output schema present, return values need not be described, and annotations carry the safety profile; params are fully covered by schema. The description supplies cost, usage, and the create_character hand-off, leaving nothing critical for an agent 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% (baseline 3), but the description adds real meaning: it explains the semantic of the 'attractive' flag (accounts whose job is to draw an audience come first) and the fallback behavior for 'app'/'category' when omitted. Only 'count' is left entirely to the schema.

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 ('Three to five ready castings for a new AI influencer') and clarifies the output form ('plain-words description ready for create_character and a first scene'). It implicitly distinguishes itself from siblings like create_character (it feeds it) and suggest_hooks/suggest_reactions, though it doesn't name those alternatives directly.

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 gives use contexts: 'Use it to suggest, to interview ("younger? a man? a different country?"), or to pick for the user,' and explains the input fallback ('with nothing, the user's app on file is used'). No explicit when-not-to-use or named sibling alternatives, so it falls 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.