Measure text

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

Annotations already declare readOnly/idempotent/non-open-world, so the safety profile is covered. The description adds real behavioral context beyond that: this tool produces no pass/fail judgment, and it names the specific metric families it reports (rhythm, opener echo, density, over-enthusiasm), which tells the agent how to treat the output.

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?

One front-loaded sentence that names the purpose first and then the metric families, with no filler. The density of rule IDs (CES-V-004, CES-S-002, CES-V-005) is somewhat opaque without context, slightly reducing readability.

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?

An output schema exists, so return values need not be described, and annotations cover safety; the description fills the remaining gap by defining the scoring intent. The only shortfall is the absent explicit routing to the sibling tools an agent would otherwise confuse this with (check_text, fix_text).

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 the single parameter's markdown-parsing behavior is fully documented in the schema. The description adds no parameter-level detail (e.g., expected size, encoding, or handling of empty input), so the baseline 3 applies.

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?

States a concrete verb and resource ("Report statistics about a text") and enumerates the metrics produced, so the agent knows exactly what comes back. It implicitly distinguishes itself from check_text via "no verdict," but never names that sibling, so the differentiation is inferential rather than explicit.

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?

"With no verdict" signals this is the diagnostic-only option versus the judging siblings, which is useful implied usage. However, there is no explicit when-to-use statement, no naming of check_text/fix_text as alternatives, and no guidance on sequencing (e.g., measure before fixing).

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