session_add_redis

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

With no annotations, the description carries the full burden of behavioral disclosure, but it only says 'set up' without describing side effects. It doesn't mention whether files are modified, dependencies installed, an existing Redis instance is required, or what role api_key plays.

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 a single terse sentence with no fluff, but it's under-specified rather than economically complete. The 'Pro feature' aside adds minimal value and there's no structural breakdown of key details.

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 mutating setup tool with no annotations, no output schema, and two parameters where only one is described, the definition is incomplete. An agent cannot confidently know what side effects to expect, what api_key is for, or what 'Pro feature' entails.

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?

The schema documents only 'directory' (as 'Project directory'), leaving api_key completely unexplained at 50% coverage. The description doesn't compensate by explaining either parameter's purpose, requiredness, or how they affect the setup.

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 ('Set up') and resource ('Redis-backed session storage'), making the tool's intent reasonably clear. However, it doesn't distinguish it from sibling tools like redis_setup_sessions or session_generate_store, and the parenthetical 'Pro feature' adds ambiguity rather than clarity.

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 alternatives. It fails to mention prerequisites, whether an existing session system is required, or when to prefer a sibling like redis_setup_sessions. The description provides no context for tool selection.

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