opencode_session_rename

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

No annotations are supplied, so the description carries the full burden. It does disclose a meaningful behavioral trait that no structured field conveys — that this is the sole mutation available against other agents' sessions — but it omits permissions required, whether the rename is idempotent or reversible, what happens on an unknown id, and 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 short sentences, front-loaded with the action and followed by the convention. The title convention is arguably better placed in the schema, but its presence here costs little and no sentence is wasted.

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 two-parameter mutation with no annotations and no output schema, the definition covers identity and naming but not failure modes, permission requirements, or return behavior. Adequate to invoke correctly in the happy path, incomplete for an agent that needs to reason about errors or side effects.

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 0%, so the description must compensate. It does so for 'title' by supplying a concrete naming convention, and the 'other sessions' clause implicitly signals that 'id' may refer to a session other than the caller's, but the exact source or format of that id is left unstated.

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: "Set the title of an opencode session." The parenthetical adds scope, clarifying that this is the only write operation applicable to sessions other than the caller's own, which helps distinguish it in a fleet of read-oriented session tools. No sibling is named as an alternative, but no sibling appears to overlap functionally.

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?

Usage is implied rather than spelled out: the title convention "<LANE>/<agent>: <task>" tells the agent how to phrase the value, and the parenthetical hints at cross-session use. There is no explicit statement of when to rename versus when not, no prerequisite that the session id must exist, and no guidance on overwriting an existing title.

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