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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is established. The description adds value beyond annotations by specifying exactly what is returned (descriptions, damage, range) and clarifying the scope (embedded items vs. world items). It does not contradict any annotation, and the added context about filters and downstream tooling is meaningful.

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 three sentences with no filler. It opens with the core action and scope, immediately distinguishes from the sibling, then lists filters and downstream uses. Every sentence earns its place, and the structure front-loads the most decision-relevant information for an agent.

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 read-only list tool with a single required parameter and clear annotations, the description covers scope, alternatives, filters, and downstream usage. It does not describe return format or pagination, but given the simplicity and the annotations, nothing essential is missing for an agent to invoke it correctly.

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% — every parameter has a description in the input schema. The description reinforces the filter semantics by naming 'type, equipped status, or hasActivities', but does not add new syntax or format details beyond what the schema already provides. The baseline of 3 is appropriate because the schema does the heavy lifting and the description adds only marginal redundancy.

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 ('List') and a specific resource ('an ACTOR's inventory'), enumerates the item categories covered, and explicitly differentiates this tool from the world Items Directory by naming the sibling 'world-item-filter'. This makes the purpose unambiguous and immediately distinguishable from related tools.

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 description gives explicit when-not-to-use guidance ('Not the world Items Directory — use world-item-filter for that') and lists the available filters (type, equipped status, hasActivities) that select the use case. It also advertises downstream consumption of item IDs by dnd5e-item-use, dnd5e-item-activate, and dnd5e-roll-attack, providing concrete context for when this tool is a prerequisite.

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