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

With no annotations, the description carries the full burden and does disclose the key trait: 'Read only', so an agent knows no transaction occurs. It also explains the conditional behavior of the wallet parameter (holdings are returned only if supplied). It does not address whether any pricing or lookup is wallet-gated, but for a read-only catalog this is largely sufficient.

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?

A single front-loaded sentence that leads with the tool's identity and ends with the most decision-relevant property ('Read only'). The nine-item enumeration is verbose, but it tells the agent what the catalog contains, so it earns most of its space.

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 one-parameter, no-output-schema, no-annotation tool, the description covers what is returned (prices and per-item holdings) and the safety profile (read only). Only the relationship to the purchase flow (prepare_dispensary_buy) 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% and already documents wallet as 'Optional: your 0x wallet, to see what you hold.' The description reinforces and slightly extends this by stating the same conditional outcome in context of prices, so it adds clarity without redundancy that harms. Nothing about format or validation is added.

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 names the specific resource (the nine one-use dispensary supplies), enumerates them, and says it returns $ZENI prices plus holdings. An agent can tell this is the dispensary catalog rather than a purchase action. It stops short of an explicit verb like 'list' and never contrasts itself with arsenal_shop or prepare_dispensary_buy.

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?

'Read only' plus the wallet-carrying option implies this is the browse-before-you-buy step, but no alternative is named and no condition is stated for choosing it over prepare_dispensary_buy or arsenal_shop. Usage is inferable rather than spelled out.

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