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

With no annotations, the description carries the burden well: it discloses the key non-obvious trait that the tool is advisory-only and does not send even when project auto-send or AI deflection is enabled, which is exactly the behavior an agent could otherwise get wrong. It also names the response contents (draft, evidence, confidence), but says nothing about cost, rate limits, or behavior when no visitor message exists.

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?

Three sentences, each doing distinct work: what it produces, the call ordering plus how to use the output, and the safety guarantee. Front-loaded with the purpose and zero filler.

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 output schema and no annotations, the description covers what matters: it enumerates the return components (draft, evidence, confidence) and the composition instruction. Gaps remain around failure modes — no visitor message, invalid conversation, or permission requirements — but the essentials for correct invocation are present.

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 project_id, project_slug and conversation_id are all documented in the schema. The description adds one real semantic point — the suggestion targets the latest visitor message, so no message selector is needed — but it explains nothing about the project_id vs project_slug choice or what happens if neither is supplied.

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 ("Generate an advisory-only HAL AI reply suggestion for the latest visitor message") and immediately distinguishes it from the send path with "advisory-only" and "never sends a message to the visitor." An agent can separate this from reply_to_conversation or get_conversation without opening any schema.

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?

"Call this after get_conversation" gives an explicit ordering constraint, and the follow-up sentence tells the agent what to do with the result when composing a final answer. It does not name the sibling that actually sends (reply_to_conversation), so the routing is implied rather than fully spelled out.

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