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

With no annotations the description carries the full burden, and it does real work: it discloses the conditional behavior (returns state only if a checkpoint exists), the exact return content, the resume-and-skip semantics, and the "(Pro)" tier gate. It omits whether the call itself mutates anything or requires further permissions, which keeps 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?

The imperative trigger is front-loaded in the first clause, and every sentence carries load: trigger, conditional outcome, fallback. No padding.

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 one-parameter, no-output-schema tool this covers what an agent needs: when to call it, what it returns, and what to do when there is no checkpoint. The absence of annotations leaves a small gap around side effects/permissions that the description does not close.

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 run_id is already fully documented in the schema, including the stable-across-restart requirement. The description adds only the framing that run_id is matched against existing checkpoints, which is marginal beyond the schema baseline.

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+resource (resume a run from a checkpoint) and defines scope: it returns the last step, state and done list. It is distinguishable from memory_save_checkpoint and memory_list_checkpoints by its resume-and-continue framing, though it never names those siblings explicitly.

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?

"Call FIRST when a run starts" gives a clear, actionable trigger, and "If none, start fresh" covers the fallback branch. It stops short of naming the complementary tools (save_checkpoint, list_checkpoints), so the routing is implied rather than explicit.

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