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

With no annotations, the description carries the full burden and does reasonably well: it discloses which duplicate survives (the first), that the result includes a removal count, and that the operation is pure CPU and instant, implying no side effects or external calls. It omits how line endings or blank lines are treated, which keeps it from 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?

Two short sentences with zero filler; the core operation and its tie-breaking rule are front-loaded, and the performance note is a single useful clause.

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 two-parameter, non-destructive utility with no output schema, the description covers the operation, the tie-break, and that a count is returned. Only the precise return shape and edge-case handling (trailing newlines, empty input) are left unstated, which is minor here.

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%, so text and ignore_case are already documented, and the baseline is 3. The description adds no parameter-level detail beyond dedupe semantics, so it neither compensates for nor detracts from the schema.

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 gives a specific verb and resource ("Remove duplicate lines") and pins down the resolution rule ("keeping the first occurrence"), so an agent can distinguish it from neighbors like data_sort or data_filter. It stops short of naming any sibling explicitly, so it doesn't earn a 5.

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?

Usage is only implied: the tool obviously applies when you have line-based duplicates, but the description never says when to prefer it over data_filter, data_sort, diff, or text_diff, nor does it state preconditions. Adequate but with a clear gap.

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