history_purge

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

Annotations only declare readOnlyHint=false, which the description is consistent with ('Remove'). The description adds genuinely useful context beyond that: the operation is destructive but partial (a tombstone remains), and it requires a two-phase dry_run/confirm flow. It does not state whether the purge is reversible or what permissions are needed, keeping it short of a 5.

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 sentences, zero padding. The destructive action and its scope lead, followed immediately by the safety workflow, so the most important information is front-loaded.

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 zero-required-parameter, six-param mutation tool with no output schema, the description covers the action, the scope options, the tombstone outcome, and the required dry-run workflow. Minor gaps remain (e.g., what the tombstone means for later reads, how doc/store interact), but an agent can call it safely as written.

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%, so the schema already documents all six parameters (all, doc, store, before, confirm, dry_run). The description adds only the confirm-comes-from-dry_run linkage, which the schema also states. Baseline 3 is correct when the schema carries the parameter semantics.

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 ('Remove undo history') plus its two scoping modes (all, or before a date) and the privacy intent, which is far more than a restatement of the name. It does not explicitly name the adjacent siblings it could be confused with (undo, restore, history_list/history_search), so an agent must infer the distinction from the verb alone.

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?

Gives an explicit operational workflow: 'Run with dry_run first, then repeat with its confirm.' This tells the agent both the required sequence and the gating mechanism, leaving nothing to inference for a destructive operation.

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