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

Annotations already declare a non-read-only, open-world, non-destructive write. The description adds genuinely new behavior: a 500-character cap on text and a moderation rule that instruction-like text is rejected with an explanation of why. That failure-mode disclosure is valuable and not derivable from the annotations, though nothing is said about rate limits or what the success response contains.

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?

It is a single front-loaded sentence with no filler; the action and content types come first and the caveats follow. The nested quotes and parenthetical slightly hurt scannability but nothing is redundant.

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 four-parameter write tool with a full schema and clear annotations, the definition covers the essentials: content kinds, length limit, reply mechanics, and the moderation rejection path. Missing pieces (whether reply_to must reference an existing post, whether the signature is displayed, error behavior on invalid input) are minor given no output schema exists.

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 all four parameters are already documented, establishing a baseline of 3. The description adds two real constraints beyond the schema — the 500-character text limit and the explicit kind/reply_to pairing — but leaves the optional 'from' signature unexplained, so the added meaning is modest.

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 ('Leave') and names the exact resource types — prayer, joy, confession, or a reply — so the agent knows precisely what the tool posts. It does not, however, distinguish itself from the closely named sibling leave_blessing, which an agent could easily confuse with this one.

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?

It does give conditional guidance: use kind "reply" together with reply_to when answering someone. But it never states when to choose this tool over leave_blessing or get_blessing, nor any exclusions, so the agent must infer the boundary between two similarly named write tools.

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