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

The description explicitly says the tool flushes Redis cache, which is a mutation of cache state, while the annotations declare readOnlyHint=true. That is a direct contradiction between the described behavior and the structured safety hint. The added detail about re-reading from MongoDB is useful but does not resolve the contradiction.

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 two sentences, front-loads the action, and adds only the operational context needed to use the parameters correctly. There is no redundant restatement of the tool name or title.

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 low-complexity cache tool with no output schema, the description covers the core action and parameter source. However, it omits what happens if both optional parameters are omitted, and the annotation contradiction undermines confidence in the tool's actual behavior.

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 0%, so the description must carry parameter meaning. It does so by naming both optional parameters and explaining they should receive cache.fq and/or cache.fqc values from a previous list_* response. It still does not explain the distinction between fq and fqc or what happens when both are omitted, but it compensates for most of the schema 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 states a specific verb and resource: "Flush a list_* tool's Redis cache." This is clearer than a tautology and scopes the action to list_* tools, but it does not explicitly distinguish this tool from siblings such as clear_collection_cache or purge_cache_group.

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?

It gives a clear usage context: pass cache.fq and/or cache.fqc from a previous list_* response so the next call re-reads from MongoDB. It does not explicitly state when not to use it or name alternative cache-clearing tools, so it falls short of full routing guidance.

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