vault_write

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

Annotations already declare destructiveHint and idempotentHint, but the description adds genuinely new behavioral facts: parent directories are created automatically, binary/NUL content is refused, and there is no automatic retry after a failure, which matters for an agent retry strategy. The overwrite-guard requirement on existing files is also disclosed. It stops short of stating permission/auth requirements or what happens on a failed guard mismatch, 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?

Extremely front-loaded: capability first, then preconditions, then side effects and failure behavior. Every clause carries information, with no filler. The telegraphic style ('copy versionGuard', 'Binary/NUL refused') trades some readability for density, which keeps it slightly below a perfect score.

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?

Since an output schema exists, return values need not be described, and the annotations carry the safety profile. Given those, the description covers the key gaps an agent needs: parents auto-created, overwrite guard requirement, content-type limits, and no retry. Residual ambiguity about how to obtain versionGuard and about path format is minor but present.

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 must carry the load. It explains the otherwise opaque ifMatch/ifMatchGuard parameters in terms of purpose (required to overwrite existing files) and even hints at the source ('copy versionGuard'), which is real added value. But path and content semantics, and the accepted sha256 format versus 16-hex guard format, are left entirely to the schema's regex patterns.

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 pair and resource: 'Create or replace UTF-8 text', which implicitly separates it from sibling tools like vault_append and vault_patch that modify rather than replace full content. It never names those siblings explicitly, so a reader must infer the boundary from the verbs.

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 precondition 'Existing files require ifMatch or ifMatchGuard' gives clear context for overwrites, which implies when this tool succeeds versus fails. However, there is no explicit guidance on when to choose vault_write over vault_append, vault_patch, or vault_replace_text, so the selection logic is inferred from the description rather than stated.

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