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

The readOnlyHint annotation already signals safety, and the description adds useful context by noting this returns summary data and no filtering is applied ('all' routines). The indication that only summary information is returned helps set expectations for the agent. It does not introduce contradictions or hidden side effects.

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 compact and front-loaded: the first sentence states what the tool lists and the key fields. The next two sentences provide usage guidance and point to the alternative. Every sentence earns its place without redundancy or filler.

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 zero-parameter, read-only listing tool with an output schema, the description covers all necessary context: what data is returned, when to use it, and when to prefer get_routine. The presence of an output schema means the description does not need to enumerate return types. No important information for correct invocation is missing.

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 tool has zero parameters, so parameter semantics are largely moot; the baseline of 4 applies. The description adds value by explaining what fields the response will contain, which indirectly clarifies what the tool offers despite having no inputs. There is no parameter ambiguity to resolve.

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: 'List all of the user's routines.' It enumerates the returned fields (name, ID, template IDs, frequency, active status), making the purpose concrete. It also distinguishes itself from get_routine by clarifying this returns summary data, not full template details.

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 gives explicit usage triggers: when the user asks 'what routines do I have?' or when a routine ID is needed. It also names the alternative, get_routine, and explains when that tool is appropriate (full template details). This leaves no ambiguity about when to select this tool over its siblings.

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