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

Annotations declare readOnlyHint=false and destructiveHint=false, so the safety profile is partly covered. The description adds the important effect that the proposal becomes unappliable, but it does not say whether the discard is reversible (relevant given the undo_changes sibling), what happens if the proposal is not open, or what permissions are required.

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?

A single tight sentence with the action and its consequence front-loaded; no filler. It could have used the remaining space for the precondition/reversibility detail, but as written it is efficient and readable.

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 mutation tool with no output schema, no parameter documentation, and no reversibility annotation, the description is too thin. It omits error/precondition behavior, permission requirements, and whether the state change can be undone, all of which an agent needs before invoking a state-mutating 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 coverage is 0%, so the schema documents nothing about proposal_id beyond its type. The description never mentions the parameter, its identifier format, or where such an ID comes from (presumably propose_changes), leaving the sole required parameter unelaborated in both places.

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?

Specific verb ('Marks ... as discarded') plus resource ('an open proposal') and a stated consequence ('so it cannot be applied'). It implies a state precondition ('open') that distinguishes it from siblings like apply_changes, but it never explicitly names or contrasts those 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 word 'open' hints at a precondition, but the description gives no explicit when-to-use guidance, no mention of what to do instead (e.g., undo_changes, apply_changes), and no note on when discarding is inappropriate. An agent must infer routing from the sibling list alone.

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