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

With no annotations, the description discloses the active subscription requirement (X-License-Key), versioning behavior, and that the payload indicates when rules changed. It does not explicitly state the tool is read-only or describe error behavior for missing/invalid keys, but the core behaviors are covered.

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?

Three sentences front-load the purpose, list contents, and convey key constraints (subscription, versioning) with no redundancy. Every sentence adds value and stays focused.

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 retrieval tool with no output schema, the description covers purpose, contents, auth, and versioning. It could be more explicit about return format, but the mention that the payload indicates when rules changed gives sufficient context for the agent to select and invoke the 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 has zero parameters, so schema description coverage is trivially 100%. No parameter details are needed, and the description appropriately focuses on the tool's purpose. A baseline of 4 for zero-parameter tools applies.

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 identifies the tool as the versioned rulebook for the Coil Live engine feed, listing its contents (cycle order, exits-first, stop derivation, day-lane rhythm, sizing, fail-closed rules). This distinguishes it from sibling tools that provide data feeds or boards.

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 states the tool is what the agent runs against get_engine_feed, implying usage to understand execution rules. It also mentions the subscription prerequisite, but does not explicitly list when not to use it or name alternatives.

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