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

No annotations are provided, so the description carries the full burden. It does disclose that the query is discarded, which is a privacy-relevant trait. However, it fails to warn that 8 of the 9 schema parameters (ref, url, city, feed, host, json, path, zone) are irrelevant to this tool's function, inviting agents to pass them expecting meaningful results. The schema labels are subtle but the description does not make the single-relevant-parameter behavior explicit.

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 purpose is front-loaded and the 'Query discarded' note earns its place as a behavioral disclosure. Efficient, though arguably over-terse for a tool with a 9-parameter schema.

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 9-parameter tool with no annotations and no output schema, the description is incomplete. It doesn't identify which parameter is relevant, doesn't clarify the return value (presumably an integer count but never stated), and doesn't warn that the other parameters are decoys. An agent cannot reliably invoke it correctly from the description alone.

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 the schema already documents all 9 parameters, including 'query: Search text; discarded after the length check.' Baseline 3 applies since the description adds no parameter meaning beyond the schema; it doesn't even explicitly name 'query' as the parameter to use.

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 specific verb (count) and resource (characters in a search query), and discloses the query is discarded. The purpose is clear on its face, but it does not differentiate from counting siblings like memory-key-count and hn-front-count, and the 9-parameter schema with unrelated fields (url, city, path) muddies what the tool actually acts on.

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?

No guidance on when to use this tool versus alternatives. Among siblings there are similar counting tools (memory-key-count, hn-front-count) and shape-check tools (domain-shape, validate-json), but the description gives the agent no criteria for selection or exclusion.

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