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

Annotations already declare destructiveHint=true, readOnlyHint=false and idempotentHint=false, so the safety profile is carried by structured data. The description adds that content is replaced wholesale (hence the patch recommendation), which is useful behavioral context, but it never says whether omitted fields are preserved or cleared in a destructive partial update.

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, target action first and the alternative second, with zero filler. The scope caveat and sibling routing are front-loaded where an agent will read them.

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?

Covers the core call and the main sibling choice, but for an 8-parameter destructive mutation with nested metadata and no output schema it leaves the partial-vs-full replacement semantics and the "VG agents only" prerequisite unexplained.

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 all eight parameters are already documented. The description only adds meaning for content (full rewrite vs. patch) and says nothing about metadata, refreshRate, or whether unset fields are left untouched; 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?

States a specific verb and resource ("Update a knowledge base document") with a scope qualifier ("VG agents only"), and explicitly names the sibling patch_kb_doc as the alternative path. An agent can distinguish this from patch_kb_doc and create_kb_doc without opening a schema.

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 routing rule: for large document bodies, prefer patch_kb_doc rather than rewriting the whole content field. It lacks guidance on the reverse case (when a full-field update is the right call vs. patch) and never explains what "VG agents only" gates, but the primary decision point is covered.

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