read_file

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

With no annotations present, the description carries the full behavioral disclosure burden. It does this well by explaining return behavior for text vs binary files, mentioning the `is_binary=True` flag, and noting configurable size limits and encoding. It does not cover error cases like missing files or permission issues, but the core behavioral traits are disclosed.

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 three sentences with no redundant words. The primary action is front-loaded, followed by essential return-format details and configurable options. Every sentence adds value.

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's simplicity and the presence of an output schema (per context signals), the description adequately covers what the agent needs: return text, binary representation, and configurable limits/encoding. It could mention error behavior but is otherwise complete for a read-only file operation.

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?

Input schema coverage is 100%, so the schema already documents path, encoding, and max_size thoroughly. The description's reference to 'configurable size limits and encoding' merely echoes the schema without adding deeper meaning, keeping this at the baseline 3.

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 the exact action ('Read a file from the filesystem') with a specific verb and resource. It is clearly distinct from sibling tools like list_dir (directory listing), search_files (searching), and write_file/patch_file (modification).

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 makes the tool's use case clear: retrieve file content from the filesystem. While it doesn't explicitly mention alternatives or exclusions, the context is direct enough that an agent can infer when to use read_file versus siblings. It lacks explicit 'use this instead of...' guidance, so it doesn't earn a 5.

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