Post a message activity

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

The description adds critical behavioral context beyond annotations, including the login requirement, the tool's limitation of not exposing the `private` argument (making all posts public), and the fact that it can update existing activities. This directly addresses side effects and limitations without contradicting the annotations.

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?

The description is three sentences long and front-loaded with the core purpose, followed by an important caveat. While slightly wordy in explaining the limitations, every sentence provides value and there is no wasted detail.

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?

Given the tool's complexity (requires login, creates/updates, public visibility), the description covers all key aspects: login, recipient targeting, update capability, privacy warning, and the mutation behavior. The output schema and parameter schemas provide additional technical detail, making the context complete.

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%, with each parameter already described in the schema. The description only briefly mentions `id` for updating and `recipientId` for the recipient, but does not add meaningful meaning beyond what the schema provides. Baseline 3 is appropriate.

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 clearly states the verb and resource: 'Post a new message-style activity to another AniList user's profile, or update an existing one by passing its `id`.' This distinguishes it from sibling tools like post_text_activity by specifying the recipient and update capability.

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 gives clear context for when to use the tool: to post a message activity to another user or update an existing one. It also explicitly warns against using it for confidential messages and mentions post_text_activity as a point of comparison, though it doesn't explicitly state alternative tools for other use cases.

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