Serial List Sessions

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

Annotations already declare readOnlyHint=true, which aligns with the description's 'List' wording. The description adds a small behavioral detail by mentioning 'port lock state' as part of the returned information. No contradictions exist, but the description does not go beyond what the read-only annotation and output schema would already suggest.

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?

The description is one concise sentence that front-loads the action and the object. Every word adds meaning, with no filler or redundant restatement of the tool name. It is efficient for an agent to parse.

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 parameterless, read-only listing tool with an output schema present, the description is sufficiently complete. It states exactly what the tool lists—active serial sessions and port lock state—and the readOnly annotation covers behavioral safety. No additional context is required for correct invocation.

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?

The tool has zero parameters, so the empty schema is fully self-explanatory and carries 100% coverage. The description does not need to add parameter semantics because there are none to clarify. This meets the baseline of 4 for no-parameter tools.

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?

The description uses a specific verb ('List') and clear resource ('active serial sessions'), and adds the unique detail of 'current port lock state.' This distinguishes it from sibling tools like serial_open_session, serial_read, and serial_close_session. An agent can understand exactly what this tool does without opening the 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?

There is no explicit guidance on when to use this tool versus alternatives such as serial_read or read_serial_snapshot. The context is implied—checking active sessions—but the description does not state a preferred use case or exclude other tools. This leaves the agent to infer selection criteria.

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