update_documents

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the safety profile is nominally covered. The description usefully adds the guardrail that an empty filter demands confirm_all=true and clarifies the single-document default, but says nothing about upsert side effects, array_filters behavior, or collation effects on matching.

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 short, front-loaded sentences with no filler; the accepted update syntax leads and the safety constraint trails. The first sentence is a fragment and the parenthetical examples are slightly dense, but nothing is wasted.

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 10-parameter mutation tool with no output schema and zero schema descriptions, the description covers only the lowest-hanging semantics. Critical call-correctness details — upsert, array_filters, collation, and connection/database scoping — are absent.

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 coverage is 0% across 10 parameters, so the description carries the full burden. It only explains update (formats), many, filter (empty case), and confirm_all; database, connection, collection, upsert, collation, and array_filters remain completely undocumented anywhere.

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?

Names the operation (update) and immediately specifies the two accepted update forms — operator document with $set/$inc or an aggregation pipeline array — which is more precise than the bare tool name. It never names replace_document, so the agent must infer the boundary between partial update and full replacement.

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 concrete selection rules for two parameters: many=false updates only the first match, and an empty filter requires confirm_all=true. It offers no guidance on when to prefer this over replace_document, upsert flows, or bulk multi-document updates.

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