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

With no annotations, the description carries the behavioral burden, and it does disclose one trait: the query is discarded after counting, implying no retention or side effects. It does not state the return format or clarify behavior when no query parameter is supplied.

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 no filler; the main action is front-loaded and 'Query discarded' is a meaningful addition. It is appropriately terse, though it could briefly mention the query parameter without losing concision.

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 simple counting tool with no output schema and no annotations, the description gives the essential purpose and disposal behavior. However, it does not explicitly identify the query parameter among nine optional inputs, name the return value, or state what happens if query is omitted – notable but not crippling gaps given the schema's clarity.

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 baseline is 3; each parameter, including 'query', is already documented in the schema. The description adds no parameter-level detail beyond labeling the resource as a search query, but the schema's 'query' field fills that gap.

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 and resource: it counts characters in a search query, which aligns with the tool name. It does not explicitly contrast with siblings like memory-key-count or hn-front-count, but the 'search query' resource sufficiently distinguishes it at a basic level.

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 implied by 'Count characters in a search query' – an agent can infer to call this when it needs the length of a query. There is no explicit when-to-use or when-not-to-use guidance, and no alternatives are named, so it stops short of clear contextual guidance.

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