encrypt_pdf

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

With no annotations, the description carries the full behavioral burden. It does well on security semantics -- clarifying that owner_password defaults to user_password and that allow_* are only viewer-enforced restrictions, which is important caveating. But it never says whether the file is modified in place or written to output_path, what overwrite controls, or what happens on a wrong current_password, leaving real gaps for a mutation 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?

Front-loaded one-line statement of the action, followed by tight clauses that each map to a parameter group. Every phrase carries information; there is no filler or repetition of the schema.

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 10-parameter file-mutating tool with no annotations and no output schema, the description covers password semantics well but omits where the result is written and how overwrite/output_path interact. An agent still lacks enough to predict side effects on the input file.

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 description coverage is 0%, so the description must compensate, and it largely does: it explains user_password vs owner_password vs current_password, enumerates all four algorithm values with the default, and characterizes the allow_print/copy/modify flags. Only input_path, output_path, and overwrite go unexplained, which keeps it short of a 5.

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?

States a specific verb and resource -- 'Add a password to a PDF' -- which unambiguously identifies the operation and implicitly separates it from the sibling decrypt_pdf. No ambiguity about which tool this is or what it produces.

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 tool name and opening sentence make the general usage obvious, and 'Use current_password if the input is already encrypted' is a useful conditional. However, there is no explicit 'use decrypt_pdf to remove a password' routing, and no statement of when this tool should not be used. Usage is implied rather than spelled out.

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