firestore_set

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

With no annotations, the description carries the full burden and does real work: it discloses that the default behavior replaces the entire document (a destructive, data-losing default) and that merge:true limits the write to top-level fields. That top-level-only nuance is a meaningful caveat an agent could not infer elsewhere. Missing are permission requirements, whether a document is created when absent, and the return shape.

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?

A single sentence using a colon to front-load the action and then the two modes. No filler, no repetition of the tool name, and the most consequential fact (replace by default) appears first.

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 annotations, no output schema, and a nested 'data' object, the description covers write semantics well but leaves gaps around return value, error behavior, and whether a missing document is created. Those omissions matter for a writer tool that an agent must call correctly on the first try.

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 100%, so the baseline is 3, but the description adds meaning beyond the schema: it clarifies that 'data' is plain JSON and that merge:true affects only top-level fields, which the terse schema description 'Merge into the existing document' does not convey. It says nothing about the 'database' parameter, however.

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 ('Write a Firestore document') and immediately contrasts the two write modes (full replace vs. merge:true). It doesn't name a sibling tool, but the replace/merge framing alone differentiates it from firestore_get, firestore_query, and firestore_delete.

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 default-vs-merge choice is well signposted, so an agent knows which mode to pick. There is no explicit when-not guidance, no mention of how this differs from creating a document that doesn't yet exist, and no alternative tool is named.

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