list_sessions

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context by explaining what each returned field means and how to interpret blocked/stuck sessions, going beyond the annotations.

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-loads the purpose well and uses scannable bullets, but the closing line about being referenced as 'DC: ...' is instruction-level metadata that does not help an agent select or invoke this specific tool, and the field list slightly overlaps the debugging heuristics.

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?

There is no output schema, so the description rightly compensates by documenting the returned fields and their interpretation. For a parameterless read-only listing tool, nothing an agent needs in order to call it correctly appears to be 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?

The tool takes no parameters (empty object schema, additionalProperties false), so there is nothing for the description to clarify; the baseline for a zero-parameter tool is 4.

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 ('List all active terminal sessions') and enumerates the returned fields (PID, Blocked, Runtime), so the agent knows exactly what this tool surfaces. It does not explicitly distinguish itself from the nearby list_processes or interact_with_process siblings, which keeps it just short of a 5.

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?

Provides concrete when-to-use guidance: verify sessions are running before sending input, and interpret 'Blocked: true' / long runtimes as signals of a stuck REPL. It lacks an explicit 'use X instead when Y' routing statement naming an alternative, so it stops short of the top score.

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