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

With no annotations provided, the description carries the full burden of disclosing behavior. It plainly states the exact behavior: the tool returns the provided text unchanged. No side effects, state changes, or external dependencies are indicated, and for an echo operation the description is sufficiently transparent.

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, clear sentence with no wasted words. Every element is meaningful, and the core behavior is front-loaded. There is no redundant information or over-explanation.

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 tool with one simple parameter, no output schema, and no annotations, the description is fully complete. It tells the agent exactly what the tool does and what is required. Nothing needed 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 schema describes the only parameter 'text' as 'Text to echo back' with 100% coverage. The description adds no additional semantic information beyond referring to 'provided text', which maps directly to the parameter. This is the baseline 3 because the schema already does all the necessary documentation.

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 'Echoes the provided text back to the caller' uses a specific verb and resource, making the tool's function immediately obvious. It clearly distinguishes this tool from its siblings: add performs arithmetic and server_time returns time, while echo simply returns the input text.

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 the usage context (when you need to return the exact text provided) but does not explicitly state when to use it over alternatives or provide any exclusions. Since the tool's function is self-evident and siblings are clearly different, the lack of explicit guidance is not problematic, but it is still not explicitly stated.

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