echo

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool 'echoes back a message with 'Hello' prefix,' which implies a read-only, non-destructive operation, but it doesn't clarify aspects like error handling, performance, or side effects. For a tool with zero annotation coverage, this leaves significant behavioral gaps.

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, efficient sentence: 'Echoes back a message with 'Hello' prefix.' It's front-loaded with the core purpose, has zero wasted words, and is appropriately sized for a simple tool. Every part of the sentence earns its place by conveying essential information.

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?

Given the tool's low complexity (one parameter, no output schema, no annotations), the description is complete enough to understand the basic function. However, it lacks details on output format, error cases, or integration with sibling tools, which could enhance usability. It meets the minimum viable threshold but has clear gaps in contextual information.

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 input schema has 100% description coverage, with the 'message' parameter fully documented in the schema. The description adds no additional meaning beyond what the schema provides, such as format examples or constraints. According to the rules, when schema coverage is high (>80%), the baseline score is 3, which applies here as the description doesn't compensate with extra param info.

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: 'Echoes back a message with 'Hello' prefix.' It specifies the verb ('echoes back') and the resource ('a message'), making it easy to understand what the tool does. However, it doesn't differentiate from sibling tools like 'add' or 'debug', which could have similar communication functions, so it doesn't reach a score of 5.

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 provides no guidance on when to use this tool versus alternatives like 'add' or 'debug'. It lacks explicit context, exclusions, or prerequisites, leaving the agent to infer usage based on the tool name and purpose alone. This minimal guidance is insufficient for optimal tool selection.

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