stack_stx

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

With no annotations, the description carries the full burden and does well: it discloses that the lock begins next reward cycle rather than immediately, that it is time-committed for numCycles, that it will be refused during the prepare phase or when already staking, and that the transaction carries a staking post-condition for exactly the locked amount. It omits wallet-unlock/auth prerequisites, fee handling, and how to undo an active lock, which keeps it short of a 5.

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-loaded with the action and effect, followed by timing, prerequisite, and refusal conditions, then a clarification of non-transfer semantics. The closing tip about earning_opportunities is mildly promotional but costs one short line.

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 six-parameter mutation tool with no annotations and no output schema, the description covers mechanics, timing, and failure modes well. It leaves a gap on execution prerequisites (unlocked wallet, fee/network assumptions) and on what the caller gets back, which the agent must infer.

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% and the schema already explains all six parameters, including the advanced btcRewardAddress/signerCalldataHex/maxWithdrawalFeeSats options. The description adds the timing semantics of numCycles and the exact-amount post-condition on `amount`, but says nothing about the three optional reward-address parameters. 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 and resource (lock STX), the protocol (PoX-5), the required collaborator (signer manager), and the payoff (sBTC rewards). It is clearly distinguishable from neighbors like extend_stacking, unstake_stx, and list_stacking_signers.

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?

Explicitly routes the agent to list_stacking_signers to choose a manager and to extend_stacking if the address is already staking, and names a hard precondition (refused during the prepare phase). It does not, however, say when to prefer stack_stx over related stacking entry points such as pillar_direct_stack_stx or stackspot_join_pot.

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