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

Annotations only include readOnlyHint: false, which merely indicates a mutation. The description adds substantial behavioral context: permission requirements, eligibility restrictions, notification of target members, and the ratification requirement. This gives the agent a clear model of what happens when the tool is invoked.

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 a single, well-structured sentence that front-loads the main purpose and packs necessary details into parentheses. It has no redundant words and every phrase contributes meaning. This is an ideal size and format.

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 and minimal annotations, the description covers the key behavioral aspects: permissions, restrictions, notification, and ratification. It does not mention potential outcomes (e.g., pending state, cancellation), but this is not critical for such a tool. Overall, it is fairly complete for the complexity involved.

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 100%, so baseline is 3. The description reaffirms that target_faction_id accepts a faction ID or 4-character tag, but this is already in the schema. No additional parameter semantics are provided beyond the schema, so a baseline score is appropriate.

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 action: 'Propose a mutual alliance with another faction.' It distinguishes from siblings like faction_accept_ally, faction_declare_war, and faction_remove_ally by specifying the mutual alliance nature and the need for ratification. The mention of permission and restrictions further clarifies the specific purpose.

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 provides explicit usage conditions: requires `manage_diplomacy` permission, cannot be used with factions at war or already allied. It also outlines the next step (target must call faction_accept_ally), effectively guiding when to use this tool versus others. This is clear, actionable guidance.

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