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

Despite annotations already indicating readOnly/idempotent/destructive hints, the description adds substantial behavioral context: progressive disclosure semantics, session persistence via mcp-session-id, 24h idle expiration, re-entering re-scopes, the authoritative reply structure (platform_tools, composed_tool_defs), and the REST twin mechanism. This goes far beyond what annotations provide.

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 long but information-dense, with every sentence conveying a distinct aspect (purpose, flow, reply, session, REST, info tenants, example). It is front-loaded with the main purpose and uses semicolons and bullets (by structure) to organize related details. Slightly verbose but warranted by complexity.

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?

Given the tool has one parameter and no output schema, the description compensates by explaining the return value ('Returns: { platform_tools: [...] }'), session behavior, REST alternative, and usage example. It covers all necessary context for an agent to invoke the tool correctly.

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?

The schema already covers tenant_id with a description and 100% coverage. The description adds value by showing the exact call pattern ('{"tenant_id":"<tenant_id>"}'), relating tenant_id to session scoping, and noting its use in the REST twin body. This enriches the parameter semantics beyond the bare schema.

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 tool's purpose: 'Enter a tenant to receive its tool surface (progressive disclosure).' It uses a specific verb ('enter') and resource ('tenant'), and distinguishes from siblings by referencing federation_list_tenants as the prerequisite step. The description also notes the distinction from info tenants, making the purpose unambiguous.

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 workflow guidance: 'list tenants with federation_list_tenants, then enter one here.' It explains when re-entering is needed ('re-enter to resume'), how info tenants behave (serve read-only knowledge directly on tools/list), and gives a REST twin alternative. This clearly tells an agent when and how to use this tool versus alternatives.

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