shop

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

With no annotations, the description carries full burden. It reveals that pricing depends on 'today's loop and their state of mind', hinting at dynamic pricing tied to game state and NPC mood. However, it does not state whether the tool is read-only, request cost, or return format. It adds some behavioral context but is incomplete.

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 extremely concise at 11 words, but it lacks an action verb and front-loads a metaphor rather than the tool's function. The structure does not efficiently convey the core operation, though it is short. A more actionable phrasing would improve clarity without adding 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?

For a simple tool with one parameter and no output schema, the description is incomplete. It does not specify what the tool returns (e.g., a list of items, prices, quantities), whether it requires the NPC to be present or in a trading state, or how to interpret the output. The hint about pricing is insufficient for effective use.

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 input schema has one required parameter 'npc_key' with no description (schema coverage 0%). The tool description does not explain what 'npc_key' represents, how to obtain it, or its purpose. Since schema coverage is low, the description must compensate, but it provides no parameter-level information, leaving the agent without necessary context.

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 is poetic but vague, stating 'A merchant's shelves' without an explicit verb. It requires inference to understand that the tool likely displays items for sale, but does not clearly distinguish from siblings like 'buy' or 'look'. A clearer purpose statement would be 'View a merchant's inventory of items for sale'.

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 guidance is provided on when to use this tool versus siblings such as 'buy', 'sell', or 'look'. The description does not specify that it should be used to browse before purchasing, nor does it mention any prerequisites like being in the same location as the NPC. The agent receives no usage context.

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