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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false; the description's main added value is resolving the 'toggle' vs. explicit set-state ambiguity, confirming the call is deterministic rather than a flip. It adds nothing about tenant-scoping refusal behavior beyond what the schema states, and no return-value context.

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?

Two short sentences, zero padding, and the core action is front-loaded before the parameter hint. Nothing could be removed without losing information.

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 an output schema, full parameter documentation, and rich annotations, the description only needs to establish purpose and pin semantics, which it does. The remaining gap is its silence on how this relates to hide_toggle and whether pinning affects any listing order for the agent.

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 100%, so all three parameters (including the conditional tenant_slug with its fallback instructions) are already fully documented. The description's restatement of pinned=true/false duplicates the schema rather than adding format or edge-case detail, so the baseline 3 applies.

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+resource: 'Toggle a project's sidebar-pin state', which is concrete and distinguishable from kb_groups_pin_toggle by the resource. However, it never mentions kb_projects_hide_toggle, another closely related project-visibility operation, so sibling differentiation is only partial.

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 says how to invoke (pinned=true to pin, false to unpin) but not when to choose this over kb_projects_hide_toggle or when a pin should be set versus left alone. Usage is implied by the tool name rather than stated, and no exclusions or prerequisites are given.

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