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

With no annotations the description carries the full burden, and it does disclose the key traits: read-only with no receipt minted, the name-first-word heuristic nature, and the hard inability to auto-discover inventory. It omits behavior on malformed or empty input (errors, ranking ties), which keeps 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?

Three sentences, front-loaded with the core action and free of filler. Slightly dense parentheses aside, but every clause adds a distinct fact.

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 explanation, and the heuristic plus read-only constraint are covered. The unexplained 'notes' parameter and the undocumented structure of inventory entries, against 0% schema coverage, leave it only partially complete for a nontrivial ranking tool.

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 description coverage is 0% and the description must compensate, but it only characterizes the inventory argument loosely ('list of MCP tools'). The shape of inventory items and the entire 'notes' parameter are left unexplained in both schema and description, leaving a real gap.

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 states a specific verb and resource ('Rank a CALLER-PROVIDED list of MCP tools by worst-regret') and immediately qualifies the scope with the heuristic used. It clearly distinguishes itself from the mint_*/verify_* siblings by stating it mints no receipt, so an agent can route correctly without opening the 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?

It gives a real usage constraint ('Cannot auto-discover the inventory -- MCP does not allow that; the caller must pass it in') and implies its read-only role versus receipt-minting siblings. However, it never states when to reach for this tool versus check_egress or gate_decision, so selection guidance is only implied.

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