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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds useful context about the guide's content scope and the 'call once' behavior, though it does not describe the form of the returned guidance material.

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?

Two sentences, zero waste: the first defines content scope and the second gives the usage rule. Purpose is front-loaded and the call-frequency instruction follows directly.

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 zero-parameter, read-only guide tool with no output schema, the description supplies everything needed: what it explains, when to invoke it, and how often. Nothing an agent needs in order to call it correctly is missing.

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 no parameters, so there are no parameter semantics to explain. The baseline for zero-parameter tools is a 4.

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 gives a specific verb ('Explains') and a clearly bounded resource (how to build flows), then enumerates the covered topics: edits, buttons, select menus, templates, placeholders and rules. This distinguishes it from sibling tools like edit_flow or get_blocks, which perform actions rather than explain concepts.

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 explicitly states the trigger: 'Call it once before creating or editing a flow.' That is clear when-to-use guidance, including a one-time constraint. It does not name an alternative or exclusion, but no obvious competing guide tool exists among the siblings, so this is strong but not exhaustive.

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