set_session_name

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

readOnlyHint=false already signals a mutation. The description contributes beyond that by disclosing that the underlying Claude Code session is not actually renamed—only the monitor's record changes—which prevents a false assumption. It says nothing about permissions, persistence, or failure behavior when threadId is invalid.

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?

A single front-loaded sentence with the purpose first and the important caveat parenthetically attached. Nothing extraneous, though the caveat could be clearer about impact on the caller.

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 mutation tool with no output schema, 0% parameter coverage, and an unaddressed sibling overlap with update_session, the description leaves too much to inference for reliable invocation.

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% for two required parameters. The description implies 'name' maps to the conversation name but never explains what threadId identifies or its format, so it fails to compensate for the documentation gap.

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 names a specific verb and resource (rename the conversation's name) and adds a genuinely useful caveat that it only changes the observer's record, not the Claude Code session itself. It does not, however, distinguish this from the sibling update_session, which appears to overlap.

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?

There is no guidance on when to use this versus update_session, no prerequisites (e.g., must the session exist or be active), and no when-not-to-use conditions. The agent must infer the selection from the name alone.

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