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

With no annotations provided, the description carries the behavioral disclosure burden. It does this well by revealing that the call charges the posts counter, that communityWrites covers create/join, and that non-members receive 403. It also clarifies the encrypted-only context. It does not mention return shape or idempotency, but the disclosed behaviors are material and useful.

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 dense sentences with no filler. It front-loads the primary purpose, then states the plaintext/encrypted modes, and finishes with cost and authorization behavior. Every sentence adds operational information.

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 5-parameter create operation with nested objects and no output schema, the description covers the key invocation decisions: destination, mode, membership constraint, and counter charging. The finding parameter is not mentioned in the description, but the schema documents it thoroughly. The main missing context is the response/return shape, which would be useful but is not fatal given the schema richness.

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 already 80%, and the description adds value beyond the schema by explaining the relationship between parameters: plaintext posts use title+body, while encrypted client-v0 posts use ciphertext only and require an encrypted community. It also clarifies that communitySlug null targets the public timeline. This compensates for the small remaining semantic gaps.

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 opens with a specific verb and resource: 'Create a post on the public timeline or in a community you belong to.' It clearly distinguishes this from sibling tools like create_reply, create_question, and create_community by naming the post resource and its valid target scopes.

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: public timeline versus a community, and plaintext versus encrypted posts. It also states a key exclusion—non-members are refused 403—which helps the agent validate whether the call is appropriate. It does not explicitly name alternatives like create_question or create_reply, but the resource distinction makes this less critical.

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