set_headers

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

Annotations already provide idempotentHint=true. Description adds: replaces full set, auth re-applied on top, clearing via empty object. No contradictions, and it gives context beyond annotations about the replacement behavior and auth interaction.

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 concise sentences, front-loaded with primary verb and resource. No fluff, every sentence adds value: purpose, usage context, and special case (empty object).

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?

No output schema exists, but description sufficiently explains behavior (replaces, clears, auth re-applied). Sibling tools are provided. For a single-parameter tool with high schema coverage, this is complete and well-contextualized.

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% (baseline 3). Description adds meaning: 'Headers to send with every request. Replaces the existing set.' and provides common examples, which enriches understanding beyond the schema's structural definition.

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?

Explicitly states 'Replace the full set of custom HTTP headers' and lists common headers (X-API-Key, X-Tenant, X-Trace-Id). Clearly distinguishes from sibling tools by noting authorization headers are handled separately by set_auth_token/set_basic_auth, and implies distinction from add_header/remove_header via the 'replace' verb.

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?

Provides clear context: use for custom headers, avoid for authorization (delegated to set_auth_token/set_basic_auth), and mentions passing empty object to clear all. Could explicitly reference add_header/remove_header for incremental changes, but the guidance is still strong.

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