list_mass_signals

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

Annotations carry the safety profile (readOnly, idempotent, non-destructive), and the description goes well beyond them by disclosing that the tool is a functional no-op, why (UMassSignalSubsystem::NamedSignals is protected with no enumeration API), and the consequence that unknown signals silently no-op. This is exactly the behavioral context annotations cannot express.

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?

Front-loads the critical fact (always empty, do not use for discovery) in the first clause, then gives the reason, the redirect, and the return shape. Every sentence earns its place with no filler.

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 no output schema, the description compensates by spelling out the exact return shape, and it fully explains the capability gap and the workaround. An agent has everything needed to decide whether to call it and what to expect.

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 the schema baseline of 4 applies. The description adds the return shape ({ count: 0, signals: [], note }) which is useful even though there are no inputs to document.

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+resource (list mass signals) and immediately distinguishes itself by declaring it always returns an empty list, which no sibling even hints at. An agent can tell it apart from fire_mass_signal and the other mass_* tools without opening any schema.

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?

Explicit when-not ('do not use it to discover signal names') and names the correct alternative with the exact condition for using it ('Call fire_mass_signal directly with a name you already know'). Nothing is left to inference.

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