host_check

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

The description adds real behavioral context beyond the annotations: it does not rewrite the host manifest, but it does write an audit event, so repeated calls produce new records. That explains the readOnlyHint=false and idempotentHint=false flags, though it does not describe failure modes or what a failed validation returns. The return shape is listed, which is slightly redundant with the output schema.

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?

Four tight sentences that front-load purpose, then usage, prerequisite, side effects, and return summary. Efficient overall, though the return-value sentence partially duplicates the output schema and could be trimmed.

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 validate-plus-audit tool with a simple 3-parameter schema and an existing output schema, the description covers purpose, prerequisites, side effects, and sibling routing. Nothing an agent needs to call it correctly 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?

Schema coverage is 100%, so host_id, max_chars, and max_lines are already documented with defaults and usage notes. The description adds nothing about parameters, which is acceptable given the schema does the heavy lifting, but it means no value beyond structured data.

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?

States a specific verb+resource pair: 'Validate an existing agent host instruction manifest and record the validation result.' It is clearly distinguishable from the nearby siblings host_setup (which creates) and doctor (broader diagnostics), both of which are named.

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?

Gives explicit when-to-use ('after host_setup or to diagnose host readability'), an explicit alternative ('use doctor for broader diagnostics'), and a prerequisite ('Requires initialized project memory'). Little is left to inference.

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