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

Beyond annotations (readOnly, idempotent), the description discloses that denied-lineage China signals return rights metadata instead of values, and that max_rows caps are reported with the true total rather than silently. This adds concrete behavioral context not present in the structured fields.

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 front-loaded with the core purpose and then expands. The long enumeration of eval signals is dense but each item adds specific value, so it earns its space. It is not succinct, but the complexity 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?

Even without an output schema, the description covers return behavior for permitted signals, denied signals, and each eval signal, plus the max_rows cap reporting and prerequisite list_signals call. An agent has everything needed to call the tool correctly.

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 coverage is 100%, so baseline is 3, but the description adds meaningful semantics: it explains that max_rows caps are reported explicitly and that list_signals should be called first to get valid names. This goes beyond the schema's simple field descriptions.

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 opens with 'Read one named signal,' a specific verb+resource statement. It then clarifies the two output categories (bounded payload vs. restricted rights metadata) and explicitly distinguishes from gfw_reading, so an agent can tell them apart without opening schemas.

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 instructs to call list_signals first to discover valid names, and explicitly names gfw_reading as the alternative for a combined view. It also gives per-signal usage notes (e.g., read 'eval-assurance' before making validity claims), covering when and when not to use the tool.

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