replay_session

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

With no annotations, the description carries the full burden and does so well: it discloses the signed-manifest verification, the single approval card in the side panel, and that execution is gated on user approval of that exact manifest hash, plus that FSB opens the tabs itself. The remaining gap is what the call returns and whether it blocks until approval, which an agent would want to know.

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?

Three front-loaded sentences, each carrying distinct load: purpose, approval mechanism, and operational constraint, with sibling routing last. No filler.

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 one-parameter tool with no output schema and no annotations, the description covers the critical unknowns: the human approval gate and tab creation behavior. It stops short of describing the response shape or the outcome of a rejected approval, a minor but real omission.

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% and the single sessionId parameter is already documented as coming from list_sessions. The description's 'Related: list_sessions (find a session)' merely restates that, adding no syntax or format detail beyond the 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 and resource ('Request replay of a recorded session') and immediately differentiates itself from siblings by naming get_session_replay and list_sessions with their distinct roles. An agent can distinguish this from the inspection-only sibling without opening either 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?

Explicitly orders the workflow: inspect with get_session_replay first, locate the session with list_sessions, then replay. It also gives a clear negative instruction ('never ask the user to open target pages manually'), removing a likely agent misstep.

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