frame

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

Annotations already declare readOnlyHint and idempotentHint, so the description correctly does not restate those. It adds useful behavioral context beyond annotations: the per-line locals timeline is only available when the run was recorded with `--focus`, and the tool reports either a return value or a raise.

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 short and front-loaded with the core purpose ('one activation in full'), and the rest of the sentence packs in the key behavioral condition without filler. It is slightly telegraphic but every phrase earns its place.

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?

With no output schema, the description does explain what the tool returns: arguments, return/raise, and the conditional locals timeline. It also tells the agent where frame ids originate. It could be more explicit about the two addressing modes (`fn`/`nth` vs `frame`), but overall it is adequate for selecting and invoking the tool.

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 core parameter meanings are already in the schema. The description adds a small amount of context by clarifying that frame ids come from sibling tools, but it does not explain the relationship between `fn`/`nth` and `frame`. Baseline 3 is appropriate.

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 identifies the resource ('one activation in full') and the key output contents: arguments, return/raise, and per-line locals timeline. It lacks an explicit verb like 'show' or 'return', so it is not quite a 5, but it is clear enough to distinguish the tool's purpose from siblings.

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?

The description implies when to use the tool by stating that frame ids fN come from `exceptions`, `tree`, and `grep`, which tells an agent where to obtain a valid frame reference. It does not explicitly state when to prefer this tool over alternatives or when not to use it, so guidance remains implicit.

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