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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful nuance ("one per card", "when measured") about what is returned, but says nothing about pagination, result caps, or ordering for a list operation.

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 sentences, front-loaded with the verb and resource, and the field list is packed efficiently. The trailing CSV sentence is slightly out of place for an MCP tool description (it points at an HTTP endpoint), but it is short and potentially useful.

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?

An output schema exists, so return values need not be re-explained, and annotations carry the safety profile; the description is nonetheless sufficient for a simple single-parameter list tool. Only pagination/limit behavior is left unstated, which is a minor gap.

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?

There is a single optional parameter and schema description coverage is 100%, with the enum values fully enumerated in the schema. "Filter by state" in the description adds no syntax or semantics beyond what the schema already provides, so the baseline of 3 applies.

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 (List) and resource (keywords in the Content Planner) and even enumerates the returned fields, so the agent knows exactly what comes back. It scopes to the Content Planner, which separates it from generic listers, but it never names a sibling tool (e.g. list_articles, list_questions) to disambiguate.

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?

"Filter by state" implies the filtering use case, and the CSV sentence gives a when-to-use alternative — but the alternative is a raw REST endpoint, not a sibling MCP tool, so it doesn't help the agent choose between list_keywords and list_articles/list_questions. No exclusions or prerequisites are stated.

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