echo

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

Annotations already declare readOnlyHint=true. The description adds 'Read-only, no side effects' and explains the default JSON envelope versus raw output, which provides helpful behavioral context beyond the structured annotation.

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 three sentences long, front-loaded with the primary purpose. Every sentence adds value: the first states the main action, the second clarifies read-only nature and output format, the third gives usage context and references the sibling. No wasted words.

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 simple echo tool with no output schema, the description sufficiently explains the return type (JSON or plain text), the available options (raw), and the intended use case. It also directs to 'printf' for advanced formatting, covering the main context needed.

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?

Input schema covers 100% of parameters with descriptions. The description adds the synonym '--raw' for the raw parameter and clarifies its effect. While the schema already describes the parameters, the description provides a usage-oriented explanation that enhances understanding.

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 outputs provided text as JSON, with an optional --raw flag for plain text. It distinguishes itself from the sibling 'printf' tool by specifying that echo is for simple output, not formatted output.

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?

Explicitly says 'Use to display values or construct output strings in agent pipelines. Not for formatted output — use 'printf' for precise format control.' This provides clear when-to-use and when-not-to-use guidance, including a reference to the alternative.

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