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

Goes beyond the annotations by disclosing determinism with an explicit method version (unified-v1), that identical inputs yield identical results, and that out-of-range values return an error naming the field. That error contract and version pinning are genuinely useful and not available from readOnlyHint/idempotentHint. It stops short of describing output shape or whether partial/invalid optional inputs degrade gracefully, but with annotations already covering safety the bar is met.

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?

Three short sentences, front-loaded with what the agent gets back, then applicability, then behavioral guarantees. No filler and no repetition of the title.

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?

An output schema exists so return values need no further explanation, the five required metrics are named, optional inputs are flagged, and the failure mode is stated. Nothing an agent needs in order to call this correctly 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?

Schema coverage is 100% with per-field descriptions, ranges, and an enum whose members are individually explained, so the schema does the heavy lifting. The description only enumerates the metric names and flags active users, CAC, and LTV as optional — no formats, units, or thresholds beyond what the schema already states.

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 ('Estimates') plus the exact outputs (valuation range, 0-100 investor score, archetype, top three priorities) and the inputs they derive from. An agent can distinguish this from analyze_listing and explain_methodology 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?

The clause 'For a business the user owns or operates' gives a real applicability condition, but there is no when-not guidance and no routing against the siblings (e.g., when to use explain_methodology or analyze_listing instead). Usage is implied rather than prescribed.

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