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

The annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so safety framing is partly covered. The description adds a genuinely non-obvious behavior about masked secret values being overwritten if echoed back, which is real value beyond the annotations. It never explains why the call is flagged destructive or what else the patch can clobber, so a 3 is fair.

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 sentences, zero filler, with the core patch semantics front-loaded before the secret-handling caveat. Every clause carries information the agent needs.

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?

Covers partial-update semantics and the masked-value pitfall for a mutation tool with no output schema. The remaining hole is substantial: a nested, entirely undocumented 'variable' object means the agent cannot construct a payload from this definition alone, and the destructive flag is left unexplained.

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 0% and 'variable' is an untyped nested object with no documented fields, so the description carries the burden. 'Pass only fields to change' conveys merge semantics but never enumerates which fields exist (name, type, defaultValue, etc.), leaving the agent to guess the payload shape.

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 (patch) and resource (Convocore agent variable) keyed by variableId, and the word 'patch' plus 'pass only fields to change' distinguishes it from create_agent_variable/delete_agent_variable. It stops short of naming the sibling read tool an agent might need first, so it is clear but not fully differentiated.

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 actionable usage context: partial updates only, and an explicit exclusion ('Never send back a masked env value as defaultValue — omit it to keep the stored value') with the fallback behavior spelled out. It does not, however, say when to reach for this versus update_agent or list_agent_variables.

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