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

Annotations declare readOnlyHint=false and destructiveHint=false, so safety is partly covered. The description adds genuinely non-structured context: the required Proof account, the authenticate-then-retry loop, and the 'start_login does NOT open this tool' exclusion. It does not describe failure modes or the created object's persisted identity, so it stops short of 5.

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 clearly labeled blocks (purpose, Agent usage, ACCESS) with the core purpose front-loaded. The parenthetical Claude Code UI instruction is slightly operational noise, but the sequencing detail earns its length.

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?

With no output schema and a fully documented 3-parameter schema, the description supplies everything else an agent needs: the prerequisite chain, the consuming tool, and the auth precondition. Nothing required to invoke this 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 description coverage is 100%, so the baseline is 3. The description adds value beyond the schema by explaining that 'channels' determines approval request routing and that Telegram channel entries need a chat_id obtained via create_chat_id_discovery, tightening the meaning of the only non-obvious parameter.

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 and resource ('Create a HITL ... config') and immediately clarifies what the resource controls ('which messaging channels receive approval requests and the default timeout'). The 'Create' verb plus the resource name distinguishes it from update_hitl, delete_hitl, and list_hitls without needing schema inspection.

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 sequences this tool against named siblings: request_hitl_authorization must be called afterward, create_chat_id_discovery is required first for Telegram channels, and the config is consumed by create_confirmation. This is exactly when/when-not/alternative guidance.

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