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

With no annotations, the description carries the full behavioral burden. 'text discarded' does disclose a genuine trait (the input is not retained, implying a stateless read-only computation), which is useful. But it omits the return shape (presumably a count), determinism, and any other operational context, so it only partially compensates.

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?

At five words it is maximally terse and front-loads the operation, but it is a bare fragment rather than a structured sentence and omits information an agent needs, landing between efficient and under-specified.

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 tool with nine parameters, no annotations, and no output schema, the description is far too thin to be complete. It neither explains what is returned nor how the heterogeneous inputs map to the single counting behavior, leaving an agent unable to call it confidently.

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 each of the nine parameters is already documented in the schema. The description adds no syntax, format, or selection meaning beyond that, so the baseline of 3 applies. It notably fails to explain which input the token count is actually computed over.

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 fragment 'whitespace token count' names an operation, so an agent can infer it counts tokens. However, the resource is left ambiguous: the tool accepts nine heterogeneous inputs (ref, city, feed, host, json, etc.), none of which is generic 'text', and the description never says what is being counted. It also offers no differentiation from sibling counting/shape tools such as search-query-len, memory-key-count, or hn-front-count.

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?

There is no when-to-use guidance, no conditions, and no mention of any alternative sibling tool. The agent is left to guess when this tool is appropriate versus the many other length/shape helpers.

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