Open Serial Session

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

Annotations already declare destructiveHint=true, openWorldHint, idempotentHint=false and readOnlyHint=false. The description adds one valuable behavioral constraint not in the annotations – the approval gate. However, it doesn't explain why the operation is destructive (e.g. whether it claims/holds a serial port or can disrupt an existing session) or what happens on failure.

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?

Two sentences, front-loaded with the action, then the gating rule. Efficient and no filler, though the second sentence is dense and could be split for readability.

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 a full input schema, an output schema, and rich annotations, the description only needs to supply the routing/precondition context, which it does. The one gap is that it never mentions whether a lease must be acquired first (terminal_acquire_lease exists as a sibling), which is a plausible source of wrong invocation ordering.

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% across 11 parameters, including enums for parity, stop_bits and flow_control, so the schema carries the semantics. The description only alludes to 'profile and optional connection overrides' and adds no format or default detail beyond that. Baseline 3 is appropriate.

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: 'Open a serial terminal session from a profile and optional connection overrides'. It's clear what the tool does, but it doesn't distinguish itself from close siblings such as terminal_session_attach or terminal_acquire_lease, which an agent may confuse with opening a session.

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 an explicit precondition ('only after user approval or a terminal_get_connection_decision action of connect') and names the sibling that produces the required signal. It also carves out the exception ('explicit user-requested connections remain allowed'), so the routing rule is unambiguous.

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