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

Annotations cover the safety profile (readOnlyHint=false, idempotentHint=false, openWorldHint=true), and the description adds genuinely non-obvious behavior: adoption creates an egg that only hatches when get_creature_status is subsequently called. It does not mention whether adoption consumes credits, despite a buy_credits/get_credit_balance sibling set, so a cost-relevant detail is missing.

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?

Three tight sentences, front-loaded with the operation, then the required follow-up call, then the parameter choice rule. The 'Wraps POST /api/house/adopt' opener is mildly redundant but useful for tracing.

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, the description covers the key lifecycle (egg appears, hatches on the next status call) and the parameter decision. It omits cost/resource implications, which is the main remaining gap.

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 the baseline is 3, but the description adds interaction semantics the schema does not: leaving species_slug empty yields a random unlocked species, and family optionally constrains that randomness. That clarifies how parameters combine rather than merely restating field docs.

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 ('Adopt a new creature') plus the underlying endpoint POST /api/house/adopt, which cleanly separates it from siblings like create_species or buy_credits. An agent can tell what this does without opening the schema.

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 conditional guidance: leave species_slug out for a random species from unlocked tiers (optionally scoped by family), or pass a slug from list_species to pick directly. It also names the immediate follow-up action (call get_creature_status right away to hatch the egg), which is exactly the routing an agent needs.

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