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

Annotations already declare destructiveHint=true, but the description adds real substance: it stresses irreversibility, states exactly what is destroyed (the session plus every message), and explains how it relates to the automated retention sweep. For a destructive tool this is the right level of disclosure.

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-loads purpose and the irreversibility warning in the first two paragraphs, then uses compact Args/Returns sections. The Google-style docstring scaffolding is slightly heavier than needed for a one-parameter tool, but no sentence is filler.

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?

With no output schema, the description supplies the return contract ({'success': True, 'deleted_session_id': ..., 'deleted_messages': N} or {'error': ...}), covers the destructive semantics, and gives the motivating use case. An agent has everything needed to call it correctly and interpret the result.

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 the single parameter, so the description carries the burden, but its 'Args' entry ('The chat session's ID') merely restates the schema title 'Session Id' and adds no format, type, or sourcing detail (e.g. obtainable from list_agent_chat_sessions). Minimum viable rather than genuinely informative.

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 ('Delete one of the user's AI assistant chat sessions') and immediately scopes it ('including every message in it'). This distinguishes it from the many other delete_* siblings such as delete_family_chat_message without requiring schema inspection.

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?

Gives explicit when-to-use context: for users who want to clear a session immediately, e.g. after sharing context they no longer want stored, versus waiting for the 90-day retention sweep. It does not name sibling tools like get_agent_chat_session or list_agent_chat_sessions as sources for the ID, so it stops short of full alternative routing.

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