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

The annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds genuinely useful behavioral detail: first-occurrence ordering, optional case-insensitive matching, and the exact return contents (deduplicated text plus counts of kept/removed lines). This goes well beyond the structured annotations.

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 compact and front-loaded: it states the core behavior first, then optional behavior, then the return value. The source URL is a minor addition but is non-disruptive and every sentence earns its place.

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?

Given the rich parameter schema, a dedicated output schema, and safety-carrying annotations, the description covers everything needed to invoke the tool correctly: input format, deduplication semantics, case sensitivity, and return value contents.

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 100%, and both parameters (text, caseInsensitive) are already documented in the schema. The description reinforces the 'one item per line' requirement and the case-insensitive option, but does not add significant meaning beyond what the schema already provides.

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 uses a specific verb ('Remove') and resource ('duplicate lines from a block of text'), and clearly explains the behavior of keeping the first occurrence in original order. This makes it immediately distinguishable from text-cleaning siblings like hopi_remove_extra_spaces or hopi_remove_line_breaks.

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 makes the intended input clear ('a block of text, one item per line'), and the optional case-insensitive behavior is stated. However, it does not explicitly contrast itself with sibling text tools or say when not to use it, so usage guidance is implied rather than explicit.

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