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

Annotations already flag destructiveHint=true and idempotentHint=true, but the description supplies the concrete destructive semantics the hint only implies: the value REPLACES the existing brandContext wholesale. It then tells the agent how to avoid data loss (read with get_feed first) and how to intentionally erase it (empty string). That is exactly the context annotations cannot convey.

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 sentences, front-loaded with the action, then the downstream consumer rationale, then the destructive replacement warning. Every sentence carries distinct information; no restatement of the title or name.

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 2-parameter mutation tool with no output schema, the description covers what it writes, who reads it, how it interacts with existing state, and how to clear it. An agent has everything required to invoke it safely on the first attempt.

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?

The brandContext parameter already has a schema description, but the description adds real meaning: what kinds of content belong in it and the empty-string clearing behavior. feedId remains undescribed in both schema and description, which is a minor gap for a 2-parameter tool with 50% coverage.

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 opens with a specific verb and resource — 'Writes free-form brand context onto a feed' — and immediately enumerates the content domain (colors, fonts, voice, required image elements, do-not-use words). This clearly separates it from read-side siblings like get_feed and from template-authoring tools such as create_code_template.

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?

It gives explicit workflow guidance: read back via get_feed before designing templates, read first with get_feed if the intent is to append, and pass an empty string to clear. Both the primary use case and the two common alternatives (append/clear) are named with their selecting conditions.

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