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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds real value beyond that by disclosing the return shape (ten indicators with status, layer, weight, explanation) and defining the full status taxonomy and what Calibrating/Unknown mean. Some operational context such as freshness or caching is not stated, keeping it short of a 5.

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-loaded with what the tool returns and then a single sentence of purpose, followed by the status legend. The legend costs several clauses but each one earns its place by preventing misreading of status values. Slightly dense but not padded.

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 and no parameters, the description carries the full burden of describing the return value, and it does so thoroughly: per-indicator fields plus the meaning of every status label, including edge cases like Calibrating and Unknown. Nothing an agent needs to interpret the response is missing.

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 there is no parameter semantics to explain; the baseline of 4 applies. The description correctly implies a parameterless call returning today's fixed set.

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 resource (the ten indicators behind today's Zensei Index) and enumerates exactly what each entry carries: status, layer, weight, and explanation. An agent can tell this is the 'why' companion to the index. However, it never distinguishes itself from the similarly named sibling zensei_view_indicators, which an agent could easily confuse it with.

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?

'Use it to explain why the index sits where it does' supplies a concrete use case, implying it complements summary/today tools. But it names no alternative and gives no exclusions (e.g., when to prefer zensei_index_summary or zensei_view_indicators), so the routing decision 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.