Read a local file

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

With no annotations, the description carries the burden of behavioral disclosure. It does add useful context: size-capped, binary files refused, and MCP_CHAT_CARDS_FS_ROOT confinement. However, it does not specify the actual size cap, return format, or error behavior, leaving gaps for a read tool.

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, front-loaded with the core purpose, then adding constraints and setup info. Every sentence adds value and there is no wasted wording.

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?

Given the tool has no output schema and no annotations, the description is decent for a simple reader but lacks key details such as the exact size cap, the return value format (e.g., text content), and error handling. It covers purpose and main constraints but is not fully self-sufficient.

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%, so the description must compensate. It hints at the maxChars parameter via 'size-capped' and at path semantics via 'binary files refused' and directory confinement, but it never explicitly explains what maxChars does or how path resolution works, leaving partial compensation.

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 clearly states the tool reads a local text file for the purpose of reviewing and plugging content into cards. It distinguishes from siblings like fetch_reference by noting the file is typically generated earlier in the conversation, and it emphasizes the local nature of the file.

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 provides context that the tool is intended for files generated earlier in the conversation, implying when it should be used. It also gives a key constraint (binary files refused) and mentions an environment variable to confine reads, but does not explicitly name alternative tools like fetch_reference for remote content.

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