ssh_agent_ensure

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

With no annotations, the description must carry the full burden of behavioral disclosure. It reveals that it starts a new agent if needed and sets environment variables, which is the core behavior. However, it does not elaborate on potential side effects (e.g., environment persistence, failure handling, or whether it modifies the current shell or system-wide settings). This is adequate but not fully 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 two sentences, front-loaded with the primary purpose ('Ensure ssh-agent is running and reachable'), followed by a concise explanation and usage trigger. No wasted words; every sentence adds necessary 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?

For a tool with no parameters and no output schema, the description fully covers what it does and when to use it. It explains the action (starting agent, setting env vars) and the trigger condition. There are no missing details that an agent would need to correctly select and call this tool.

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 the baseline is 4. The description adds no parameter-specific detail (none needed), and the schema already has full coverage with an empty properties object. No additional semantic clarification is required.

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: ensuring ssh-agent is running and reachable, starting a new agent if needed, and setting environment variables. The verb 'ensure' and resource 'ssh-agent' are specific, and it distinguishes from sibling tools that focus on file operations, execution, or diagnostics.

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 an explicit trigger condition: 'Use this FIRST when SSH operations fail with agent-related errors.' This gives clear context for when to invoke the tool, though it does not explicitly mention when not to use it or suggest alternatives (e.g., other diagnostics).

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