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

Annotations only declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false. The description adds real behavioral context beyond that: the base caption is preserved and each platform publishes its own variant, clarifying this is a non-destructive additive write. It doesn't explain what happens on re-generation (non-idempotency) or platform-connection prerequisites, so not 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?

Two tightly written sentences, front-loaded with the core action and scope, with the second sentence delivering the key mutation semantics. No wasted words.

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 one-parameter generation tool with no output schema, the description covers what is produced, the platform scope, and the effect on the base caption. It stops short of describing the return shape (e.g., whether variants are returned or stored per platform) or the need for connected platforms, leaving a small gap.

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% and there is a single parameter (postId) already documented in the schema. The description's 'for one post' merely restates the schema semantics without adding format 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 (generate) and resource (platform-specific caption variants) with an explicit scope ('for one post'). It is clearly distinguishable from siblings like edit_caption (edits the base caption) and generate_posts (generates whole posts), and it names the target platforms.

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 phrase 'for one post' and the mention of 'each connected platform' imply the context of use, but there is no explicit when-to-use/when-not guidance or routing to alternatives such as edit_caption. Usage is inferable rather than stated.

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