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

Annotations already flag destructiveHint=true and openWorld=false, so the overwrite warning is consistent rather than novel, but the description adds real detail beyond them: slot-1-onward overwrite, starter text cleared vs. creator's own examples kept, per-slot return of what was saved/cleared, and "Uses no credits." The only gap is that it does not flag what happens to the previously saved set for slots beyond the new array length in explicit terms, though the overwrite model is strongly implied.

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?

Four sentences, front-loaded with purpose, then the routing rule, then the overwrite semantics, then the return and cost note. Every sentence carries decision-relevant information and none repeat the title or schema.

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 3-parameter mutation with no output schema, the description covers purpose, alternatives, destructive overwrite behavior, return summary, and cost. An agent has everything needed to call it correctly and warn the creator about clearing starter text.

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 baseline is 3, but the description adds meaning the schema lacks: the effective limit is 5 examples except 3 for the newsletter (schema only says maxItems 5), and the crucial instruction "Pass the full set" governs how the array parameter is submitted. The CTA limit of 3 matches the schema and adds little.

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?

The description uses a specific verb and resource ("saves pasted posts as the voice examples... and calls to action of one format") and states the downstream effect ("so new drafts copy that wording"). It also names the sibling it is not (import_voice_from_posts / list_my_posts), so an agent can distinguish it without opening the 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?

Explicit when-to-use: "Use it when the creator pastes their own posts or CTAs." Explicit alternative and routing condition: "to pull posts from a social account use list_my_posts and import_voice_from_posts." No inference required.

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