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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuine behavioral context: it is a one-time-per-task priming call and enumerates the contract contents. It stops short of stating pagination/rate/caching specifics, so a 4 rather than 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?

The critical usage instruction (call FIRST, once per task) is front-loaded in the opening clause. A few of the later enumerations of contract contents are slightly list-heavy, but every sentence conveys a distinct fact and 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?

With an output schema present the return values need not be explained, yet the description usefully summarizes what the contract covers and how the agent should consume it. Nothing essential for correct invocation is missing for a zero-parameter priming tool.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate — baseline 4 applies. The description correctly does not invent parameter behavior.

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 and resource — returns the complete RichDocument formatting contract for Postlyra posts, including block/inline mark JSON, nesting, limits, uploads, error recovery and presets. It is clearly distinguishable from siblings like preview_post or create_post_draft because its output is a schema/contract rather than post content.

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?

Explicitly says to call it FIRST and once per task when composing or formatting any post, and tells the agent what not to rely on ('Telegram MarkdownV2/parse_mode documentation is not needed'). It even points toward follow-up action ('which tool to use next'), giving unambiguous when/when-not guidance.

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