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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, so the agent knows this is a non-read, non-idempotent write operation. The description adds 'durable' to indicate persistence, which is useful. However, it doesn't disclose what 'durable' means in terms of storage, whether the decision is appended to a log, or any side effects beyond creation. No contradiction with annotations.

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?

One sentence, front-loaded with the core action and resource, then lists optional attributes. No wasted words. It could be slightly more explicit about the durable nature, but it's efficient and clear.

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 simple create-with-optional-fields tool, the description plus schema covers the essentials. There is no output schema, so the agent doesn't know what the return value is, but for a logging tool that may be acceptable. It doesn't mention whether the decision is immediately visible or requires a sync, but given the sibling vault_sync exists, that could be relevant. Still, the description is adequate for basic invocation.

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 the schema already documents all five parameters. The description adds a bit of context by calling the decision 'durable' and listing optional attributes, but it doesn't add meaning beyond the schema's own descriptions. Baseline 3 is appropriate.

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 specific verb ('Creates') and resource ('durable project or workflow decision') and lists optional attributes (rationale, actor, project association, tags). It clearly distinguishes this from sibling tools like vault_get_context or vault_list_handoffs, though it doesn't explicitly name a sibling alternative.

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 implies usage: use this when you need to record a durable decision. It does not explicitly state when not to use it or name alternatives, but the context of 'durable decision' versus handoff/checkpoint tools gives reasonable guidance. No exclusions or alternatives are mentioned.

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