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

With no annotations, the description carries the disclosure burden, but it only states that values are discarded. It does not mention whether the call is read-only, what happens on invalid JSON, what the returned count looks like, or whether any data is retained beyond the call.

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?

The description is extremely compact—two short sentences—and front-loads the action before the behavioral note. There is no filler, though the terseness borders on under-specification given the nine-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?

Given the absence of annotations and output schema, the tool needs a fuller description: it does not specify the input mechanism, return type, error behavior, or usage context among a long list of sibling tools. The single sentence leaves too much for the agent to guess.

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?

All nine parameters have schema descriptions, so the baseline is met, but the tool description adds no information about which parameter supplies the JSON object or how the other parameters relate to counting keys. The schema itself suggests varied shape checks, leaving the invocation somewhat ambiguous.

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 identifies a specific verb ('Count') and resource ('keys in a JSON object'), and adds a distinguishing behavioral note ('Values discarded'). It does not relate the tool name's 'memory' to the operation or explicitly differentiate it from sibling validation/shape tools, but the core action is unambiguous.

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 guidance about when to use memory-key-count over siblings such as validate-json or domain-shape, and no mention of prerequisites or typical call patterns. An agent must infer usage from the name and schema alone.

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