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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description adds meaningful output behavior: the exact fields (name, one-line description, source URL) and the guarantee that 'no denied values are returned.' It does not contradict annotations and enhances the agent's expectation of what the tool returns.

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 longer than a simple listing, but each section (the three application categories) provides essential context for an agent to decide to call it. It is front-loaded with the purpose and ends with usage guidance. While somewhat verbose, the information density justifies the length.

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?

Given that the tool has no parameters and no output schema, the description fully covers what an agent needs: what it returns, the categories of signals, and the recommended next step (get_signal). Nothing is missing for correct invocation.

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 input schema has zero parameters, which is fully covered by the schema itself (100% coverage). Per the rubric, the baseline is 4 for no parameters. The description's note that it 'takes no arguments' reinforces but does not add beyond what the schema already makes obvious.

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 uses a specific verb ('List') and resource ('published signals') and details the exact content (name, one-line description, source URL) across three named applications. It clearly distinguishes itself from the sibling get_signal by stating it returns summaries, not full readings.

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 states 'Call this first to discover signal names, then get_signal for one full reading,' providing both when-to-use and the preferred follow-up tool. This is unambiguous guidance for an agent.

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