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

There are no annotations, so the description carries the full burden. It does disclose that values are discarded, which is a useful behavioral signal and implies a read-only counting operation. However, it does not explain return format, error behavior, or what 'discarded' means operationally.

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 primary action is front-loaded, and the additional behavioral note ('Values discarded') earns its place.

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?

The tool has nine optional parameters, no output schema, and no annotations, yet the description does not explain which parameters to supply or what the return value represents. The gap between the described purpose and the actual schema makes correct invocation unclear.

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 baseline is 3. The description adds no parameter-level meaning, and the schema descriptions only say that parameters are discarded; they do not identify which parameter is the JSON object whose keys are counted.

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?

Description states a concrete operation ('Count keys') on a resource ('a JSON object') and adds that values are discarded. However, it does not connect to the tool's 'memory' name or clarify which of the nine input parameters supplies that JSON object, so it is clear but not fully self-contained.

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 is given for when to use this tool versus siblings such as validate-json, hn-front-count, or search-query-len. There are no conditions, exclusions, or alternatives mentioned, so an agent cannot decide between this and related count/validation tools.

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