Read the instance's rules and limits

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

The annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds context about the range of possible character limits and the nature of the data returned, which is beyond the annotations. It does not contradict 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 two sentences, front-loaded with the key purpose, and includes a practical tip. Every sentence earns its place without extraneous content.

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?

The tool is simple (one optional parameter) with rich annotations covering safety and idempotency. The description explains what data will be returned, fulfilling the agent's need to know what to expect. No output schema exists, but the description sufficiently enumerates the content. A minor gap is the lack of a note about account selection behavior, but the schema addresses that.

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 description coverage is 100%, so the account parameter is fully documented in the schema. The description does not add parameter-specific details, but since the schema covers it, a 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 tool reads the instance's rules and limits, enumerates specific data points (character limit, attachments, poll options, media size, software version, server rules), and distinguishes it from siblings by its focus on instance configuration rather than timelines or statuses.

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 explicitly advises reading it before drafting anything long, given the variable character limit. While it doesn't name alternative tools, it provides clear usage context that an agent can act on. No exclusion criteria are stated, but the use case is specific enough.

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