io_checkin_visitor

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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=true) by disclosing that the first call performs NO network call and returns a preview plus token, that only a repeat call with that token mutates state, and that records can attempt to induce unintended writes. This is exactly the behavioral context an agent needs for a destructive mutation.

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?

Front-loaded with the purpose, then the confirmation mechanics, then the injection warning. Every sentence carries operational weight, though the final warning sentence is dense and slightly over-long for the value it repeats.

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, the description still tells the agent what the first call returns (a preview and confirmToken). Combined with the annotations covering the destructive profile, nothing needed to call 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 coverage is 100%, so the baseline is 3. The description adds phase semantics not fully captured by the schema alone: the token must come from this same tool's phase-1 response, only after the user has seen the preview, and is ignored when the client supports elicitation.

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 ('Check in a visitor') plus the trigger context ('upon arrival at the building'), which cleanly separates it from siblings like io_checkout_visitor, io_get_visitor, and io_create_visitor 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?

Explains the confirmation flow precisely: a prompt when the client supports elicitation, otherwise a preview-plus-confirmToken two-step where the first call makes no network call. It does not explicitly name a sibling alternative, but the when-to-use condition (arrival) and the procedural branch are both stated clearly.

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