repl_list_namespace

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 agent knows this is a safe read. The description adds the return format ('JSON with variable names, types, and preview values'), which is helpful but partially redundant given the output schema. No additional context about session-not-found behavior, pagination, or preview truncation is provided.

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-loaded with the primary action, and includes a clear return summary. There is no fluff, and every word adds value. It is appropriately concise for a simple listing tool.

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 is simple, and the description covers the core operation and return format. However, it leaves out the session_id parameter explanation and any caveats about empty namespaces or invalid sessions. Given that schema coverage is 0% and output schema exists, the description should have at least mentioned the input requirement. It is adequate but has clear gaps.

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 description does not mention the required session_id parameter at all. Schema description coverage is 0%, so the tool description was expected to compensate, but it completely omits parameter semantics. The agent receives no guidance on how to specify the target session, which is critical for correct invocation.

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 clearly states the tool's purpose: 'List all variables stored in a session's namespace.' This specific verb+resource combination distinguishes it from siblings like repl_get_variable (singular) and repl_clear_namespace (delete). It is unambiguous and actionable.

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?

The description implies usage for enumerating namespace variables but does not explicitly say when to use it versus alternatives. It does not mention that repl_get_variable should be used for a single variable or provide exclusions. The context of 'all variables' gives some guidance, but it stops short of explicit comparison.

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