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

Annotations already carry destructiveHint and idempotentHint. The description adds concrete behavioral detail beyond those hints: full replacement semantics, expected_version creation behavior, request_id retry restriction, an agent-key requirement, and explicit guarantees that credentials are never stored and no AI model is called. This significantly extends what the structured annotations convey.

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?

Three sentences, each with a distinct purpose: the core action, versioning/retry semantics, and auth/privacy constraints. Information is front-loaded and there is no redundant or filler wording.

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, the description covers purpose, timing, mutation semantics, versioning, retry behavior, authentication, and privacy. Combined with the rich input schema, an agent has all the necessary information to invoke the tool correctly.

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 0%, so the description carries most of the parameter-semantics burden. It explains expected_version (0 creates versus replacement), request_id (identical retries only), and enumerates the content of the state object (goal, completed work, decisions, constraints, next actions, blockers, artifacts). It does not describe task_id explicitly, but its nominal meaning is clear from context.

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 states a specific verb and resource: 'Durably save ... before a context reset or handoff.' It enumerates the stored fields (goal, decisions, next actions, etc.) and adds 'Full replacement' versioning semantics, which clearly sets it apart from threadkeep_list and threadkeep_resume.

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 gives an explicit timing context ('before a context reset or handoff') and explains versioning and retry usage ('expected_version=0 creates a task', 'Reuse request_id only for identical retries'). It does not explicitly name sibling alternatives, but the clear context is enough for an agent to decide.

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