check_facebook_credentials

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

With no annotations provided, the description carries the full transparency burden and does it well. It discloses the credential sources (~/.facebook-automata-mcp/credentials.json and FACEBOOK_MCP_* environment variables), the exact Facebook API calls made, and the conditional /debug_token behavior depending on whether app credentials are configured.

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?

The description is two sentences with the primary purpose front-loaded. The second sentence provides concrete technical detail without fluff, earning its place by explaining the validation mechanism and conditional behavior.

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?

The description is complete for a zero-parameter, read-only check tool: it names credential sources, validation endpoints, conditional behavior, and the kind of information reported (scopes, expiry, validity). Since an output schema exists, explaining the return value shape is unnecessary.

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 input schema has zero parameters, so a baseline of 4 applies. The description correctly implies that the tool needs no arguments and instead reads from pre-existing configuration, which is all an agent needs to know.

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 'Check whether Facebook credentials are configured and still valid,' which is a specific verb plus clear resource and goal. It further explains the exact validation flow (GET /me and /debug_token), making the purpose concrete and distinguishable from credential-setting or profile-fetching siblings.

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 description implies when to use the tool: whenever an agent needs to verify that Facebook credentials exist and are still valid. However, it does not explicitly contrast itself with the similar sibling get_credentials_status or state when one should be preferred over the other.

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