Send a follow-up message to a session

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

With only openWorldHint in annotations, the description carries the behavioral burden and does add real value: it discloses that the agent retains prior context and permission level, and that allow_edits/allow_bash mutate that level persisting into later messages. It does not describe errors on invalid/expired sessions or what the call returns.

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 tight sentences, zero waste, and the core action (continue an existing session) is front-loaded before the permission-state detail.

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 4-param stateful tool with no output schema and only an openWorldHint annotation, the description covers continuation semantics, context retention, and permission persistence adequately. Minor gaps remain around failure modes and return value, but nothing essential for correct invocation 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 schema already documents all four parameters, including the 'from this message onward' semantics of the allow_* flags. The description largely restates that, adding only the framing that the level change persists across messages – the baseline 3 for fully covered schema.

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 (continue/send) and resource (existing delegated session), and the phrasing 'Continue an existing delegated session' contrasts cleanly with the sibling delegate_task, which starts a new one. An agent can distinguish it from create_session and delegate_task without reading schemas.

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?

'Continue an existing delegated session with another message' establishes the context of use, and the session_id schema note ties it to delegate_task/create_session. It never explicitly says when NOT to use it (e.g. for a new task use delegate_task), so it falls short of full routing guidance.

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