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

Beyond the readOnlyHint annotation, the description discloses meaningful behavioral details: it returns live state, is deterministic, source-traceable, and makes no model or network call. This gives an agent confidence that the operation is safe and side-effect-free without requiring structure inspection.

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 two short sentences, each earning its place. The first fronts the primary function, and the second removes any concern about network or model latency, making the text both efficient and immediately useful.

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 a zero-parameter schema and an output schema present, very little needs to be stated. The description covers what the tool returns, the core property 'deterministic', and the safety guarantee 'no model or network call', which is sufficient for an agent to correctly select and invoke it.

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 and the schema coverage is 100%, so there is no parameter meaning for the description to add. The absence of parameters is already fully represented by the empty schema, and the description appropriately focuses on behavior instead.

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 ('Return') and a specific resource ('deterministic engine manifest'), and adds clarity with 'live' and 'source-traceable'. This distinguishes it from the predictive/estimation flavors implied by sibling tools like legend_saju_read_fortune and legend_saju_analyze_compatibility.

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?

'No model or network call' gives clear context that this is an inspection tool, not a generation or prediction tool. It implies when an agent should select it — to view the engine manifest rather than obtain a reading — but it does not explicitly name alternative tools or exclusion conditions.

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