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

Annotations already declare the safety profile (not read-only, not destructive, idempotent, closed-world), so the description's real contribution is the 'open Undo' precondition and the note that the undo.id must come from the original change's response. It does not say what happens when the Undo window has lapsed, which is the main missing behavior for a reversible mutation.

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 compact sentences with the usage condition front-loaded ahead of the exclusion. The undoId sentence duplicates the schema, so a small amount of text is not earning 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 a rich annotation set, an output schema, and only two fully documented parameters, the description covers what an agent needs to decide and call it. The only material gap is the behavior when the Undo window is closed.

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 coverage is 100% and both parameters are documented in-schema, so the baseline is 3. The description's instruction to 'give the undo.id the change came back with' essentially restates the schema's undoId description rather than adding new meaning, and it says nothing extra about idempotencyKey.

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 uses a concrete verb ('take back a change') and names the resource class explicitly (a logged set, meal, weigh-in or any other). It also bounds the operation to changes made 'here' and excludes changes made in the Almost Fire app, which separates it from delete_set/edit_set/delete_food_entry without naming them directly.

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?

It gives an explicit trigger ('when the person wants to take back a change') plus a precondition (the change's Undo must still be open) and an exclusion (changes made in the Almost Fire app itself). It stops short of naming the sibling tool that handles the excluded case, so the agent must infer an alternative.

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